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Module fix for starfive_fb#5

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sarnold wants to merge 18 commits intoesmil:starlightfrom
VCTLabs:module-fix
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Module fix for starfive_fb#5
sarnold wants to merge 18 commits intoesmil:starlightfrom
VCTLabs:module-fix

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@sarnold sarnold commented May 14, 2021

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Tom and others added 17 commits May 12, 2021 11:55
[FIXME] why we can not do it in U-boot?

[geert: Rebase to v5.13-rc1]
Note: including uSDK v0.9->v1.0 patch

[geert: Rebase to v5.13-rc1]
Warnings fixed by Matteo.

Signed-off-by: Matteo Croce <mcroce@microsoft.com>
drivers/usb/cdns3/
drivers/usb/core/
drivers/usb/host/
include/linux/usb.h

[geert: Rebase to v5.13-rc1]
1, add ov5640&sc2235 drivers, update stf_isp
2, add MIPI/CSI/DSI drivers for VIC7100
Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
This IP is also used on the Starfive JH7100 riscv64 SoC and presumably
also the upcoming JH7110 SoC.

Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
Descriptor management was simplified with commit:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ef6fb2d6f1abd56cc067c694253ea362159b5ac3

Code added to dw-axi-dmac-platform driver due to VIC7100 Cache Coherency
issues needed follow those changes.

Signed-off-by: Michael Scott <mike@foundries.io>
The BeagleV Starlight v0.9 board doesn't have the IRQB line from the
pmic routed to the SoC, so this hack is needed to allow the driver
to be loaded without it. See
beagleboard/beaglev-starlight#14

Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
This is the device tree from https://github.com/starfive-tech/u-boot/
Rearranged, cleanups, fixes and TPS65086 added by Emil.
Cleanups, fixes and LED added by Geert.

Signed-off-by: yanhong.wang <yanhong.wang@starfivetech.com>
Signed-off-by: Huan.Feng <huan.feng@starfivetech.com>
Signed-off-by: ke.zhu <ke.zhu@starfivetech.com>
Signed-off-by: yiming.li <yiming.li@starfivetech.com>
Signed-off-by: jack.zhu <jack.zhu@starfivetech.com>
Signed-off-by: Samin Guo <samin.guo@starfivetech.com>
Signed-off-by: Chenjieqin <Jessica.Chen@starfivetech.com>
Signed-off-by: bo.li <bo.li@starfivetech.com>
Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
For convenience this also adds a small starlight_defconfig and the
firmware needed for the brcmfmac driver along with the signed regulatory
database.

The firmware is from the linux-firmware repo and the regulatory database
from the wireless-regdb Fedora package.

Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
esmil pushed a commit that referenced this pull request May 14, 2021
[ Upstream commit bbd6f0a ]

In bnxt_rx_pkt(), the RX buffers are expected to complete in order.
If the RX consumer index indicates an out of order buffer completion,
it means we are hitting a hardware bug and the driver will abort all
remaining RX packets and reset the RX ring.  The RX consumer index
that we pass to bnxt_discard_rx() is not correct.  We should be
passing the current index (tmp_raw_cons) instead of the old index
(raw_cons).  This bug can cause us to be at the wrong index when
trying to abort the next RX packet.  It can crash like this:

 #0 [ffff9bbcdf5c39a8] machine_kexec at ffffffff9b05e007
 #1 [ffff9bbcdf5c3a00] __crash_kexec at ffffffff9b111232
 #2 [ffff9bbcdf5c3ad0] panic at ffffffff9b07d61e
 #3 [ffff9bbcdf5c3b50] oops_end at ffffffff9b030978
 #4 [ffff9bbcdf5c3b78] no_context at ffffffff9b06aaf0
 #5 [ffff9bbcdf5c3bd8] __bad_area_nosemaphore at ffffffff9b06ae2e
 #6 [ffff9bbcdf5c3c28] bad_area_nosemaphore at ffffffff9b06af24
 #7 [ffff9bbcdf5c3c38] __do_page_fault at ffffffff9b06b67e
 #8 [ffff9bbcdf5c3cb0] do_page_fault at ffffffff9b06bb12
 #9 [ffff9bbcdf5c3ce0] page_fault at ffffffff9bc015c5
    [exception RIP: bnxt_rx_pkt+237]
    RIP: ffffffffc0259cdd  RSP: ffff9bbcdf5c3d98  RFLAGS: 00010213
    RAX: 000000005dd8097f  RBX: ffff9ba4cb11b7e0  RCX: ffffa923cf6e9000
    RDX: 0000000000000fff  RSI: 0000000000000627  RDI: 0000000000001000
    RBP: ffff9bbcdf5c3e60   R8: 0000000000420003   R9: 000000000000020d
    R10: ffffa923cf6ec138  R11: ffff9bbcdf5c3e83  R12: ffff9ba4d6f928c0
    R13: ffff9ba4cac28080  R14: ffff9ba4cb11b7f0  R15: ffff9ba4d5a30000
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018

Fixes: a1b0e4e ("bnxt_en: Improve RX consumer index validity check.")
Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Reviewed-by: Andy Gospodarek <gospo@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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sarnold commented May 14, 2021

Lemme fix this (actually I didn't want that first commit on this branch).

Signed-off-by: Stephen L Arnold <nerdboy@gentoo.org>
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esmil commented May 14, 2021

Hi Steve. Thanks for the fix. Yeah, I was going to ask if you'd tried the starlight_defconfig I added here. I can just cherry-pick the module fix if that's easier.

@sarnold sarnold changed the title Module fix and minmal SDK defconfig Module fix for starfive_fb May 14, 2021
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sarnold commented May 14, 2021

Already done ;)

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esmil commented May 14, 2021

Great thanks! I ended up reordering the commits anyway. Hope you don't mind.

@esmil esmil closed this May 14, 2021
@sarnold sarnold deleted the module-fix branch May 16, 2021 00:03
esmil pushed a commit that referenced this pull request May 17, 2021
Commit 4af22de ("arc: fix memory initialization for systems
with two memory banks") fixed highmem, but for the PAE case it causes
bug messages:

| BUG: Bad page state in process swapper  pfn:80000
| page:(ptrval) refcount:0 mapcount:1 mapping:00000000 index:0x0 pfn:0x80000 flags: 0x0()
| raw: 00000000 00000100 00000122 00000000 00000000 00000000 00000000 00000000
| raw: 00000000
| page dumped because: nonzero mapcount
| Modules linked in:
| CPU: 0 PID: 0 Comm: swapper Not tainted 5.12.0-rc5-00003-g1e43c377a79f #1

This is because the fix expects highmem to be always less than
lowmem and uses min_low_pfn as an upper zone border for highmem.

max_high_pfn should be ok for both highmem and highmem+PAE cases.

Fixes: 4af22de ("arc: fix memory initialization for systems with two memory banks")
Signed-off-by: Vladimir Isaev <isaev@synopsys.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: stable@vger.kernel.org  #5.8 onwards
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
mcd500 pushed a commit to mcd500/linux-jh7100 that referenced this pull request May 17, 2021
…rallel

[ Upstream commit b168e1d ]

We got a warning message below.
When server tries to close one session by force, it locks the sysfs
interface and locks the srv_sess lock.
The problem is that client can send a request to close at the same time.
By close request, server locks the srv_sess lock and locks the sysfs
to remove the sysfs interfaces.

The simplest way to prevent that situation could be just use
mutex_trylock.

[  234.153965] ======================================================
[  234.154093] WARNING: possible circular locking dependency detected
[  234.154219] 5.4.84-storage esmil#5.4.84-1+feature+linux+5.4.y+dbg+20201216.1319+b6b887b~deb10 Tainted: G           O
[  234.154381] ------------------------------------------------------
[  234.154531] kworker/1:1H/618 is trying to acquire lock:
[  234.154651] ffff8887a09db0a8 (kn->count#132){++++}, at: kernfs_remove_by_name_ns+0x40/0x80
[  234.154819]
               but task is already holding lock:
[  234.154965] ffff8887ae5f6518 (&srv_sess->lock){+.+.}, at: rnbd_srv_rdma_ev+0x144/0x1590 [rnbd_server]
[  234.155132]
               which lock already depends on the new lock.

[  234.155311]
               the existing dependency chain (in reverse order) is:
[  234.155462]
               -> esmil#1 (&srv_sess->lock){+.+.}:
[  234.155614]        __mutex_lock+0x134/0xcb0
[  234.155761]        rnbd_srv_sess_dev_force_close+0x36/0x50 [rnbd_server]
[  234.155889]        rnbd_srv_dev_session_force_close_store+0x69/0xc0 [rnbd_server]
[  234.156042]        kernfs_fop_write+0x13f/0x240
[  234.156162]        vfs_write+0xf3/0x280
[  234.156278]        ksys_write+0xba/0x150
[  234.156395]        do_syscall_64+0x62/0x270
[  234.156513]        entry_SYSCALL_64_after_hwframe+0x49/0xbe
[  234.156632]
               -> #0 (kn->count#132){++++}:
[  234.156782]        __lock_acquire+0x129e/0x23a0
[  234.156900]        lock_acquire+0xf3/0x210
[  234.157043]        __kernfs_remove+0x42b/0x4c0
[  234.157161]        kernfs_remove_by_name_ns+0x40/0x80
[  234.157282]        remove_files+0x3f/0xa0
[  234.157399]        sysfs_remove_group+0x4a/0xb0
[  234.157519]        rnbd_srv_destroy_dev_session_sysfs+0x19/0x30 [rnbd_server]
[  234.157648]        rnbd_srv_rdma_ev+0x14c/0x1590 [rnbd_server]
[  234.157775]        process_io_req+0x29a/0x6a0 [rtrs_server]
[  234.157924]        __ib_process_cq+0x8c/0x100 [ib_core]
[  234.158709]        ib_cq_poll_work+0x31/0xb0 [ib_core]
[  234.158834]        process_one_work+0x4e5/0xaa0
[  234.158958]        worker_thread+0x65/0x5c0
[  234.159078]        kthread+0x1e0/0x200
[  234.159194]        ret_from_fork+0x24/0x30
[  234.159309]
               other info that might help us debug this:

[  234.159513]  Possible unsafe locking scenario:

[  234.159658]        CPU0                    CPU1
[  234.159775]        ----                    ----
[  234.159891]   lock(&srv_sess->lock);
[  234.160005]                                lock(kn->count#132);
[  234.160128]                                lock(&srv_sess->lock);
[  234.160250]   lock(kn->count#132);
[  234.160364]
                *** DEADLOCK ***

[  234.160536] 3 locks held by kworker/1:1H/618:
[  234.160677]  #0: ffff8883ca1ed528 ((wq_completion)ib-comp-wq){+.+.}, at: process_one_work+0x40a/0xaa0
[  234.160840]  esmil#1: ffff8883d2d5fe10 ((work_completion)(&cq->work)){+.+.}, at: process_one_work+0x40a/0xaa0
[  234.161003]  esmil#2: ffff8887ae5f6518 (&srv_sess->lock){+.+.}, at: rnbd_srv_rdma_ev+0x144/0x1590 [rnbd_server]
[  234.161168]
               stack backtrace:
[  234.161312] CPU: 1 PID: 618 Comm: kworker/1:1H Tainted: G           O      5.4.84-storage esmil#5.4.84-1+feature+linux+5.4.y+dbg+20201216.1319+b6b887b~deb10
[  234.161490] Hardware name: Supermicro H8QG6/H8QG6, BIOS 3.00       09/04/2012
[  234.161643] Workqueue: ib-comp-wq ib_cq_poll_work [ib_core]
[  234.161765] Call Trace:
[  234.161910]  dump_stack+0x96/0xe0
[  234.162028]  check_noncircular+0x29e/0x2e0
[  234.162148]  ? print_circular_bug+0x100/0x100
[  234.162267]  ? register_lock_class+0x1ad/0x8a0
[  234.162385]  ? __lock_acquire+0x68e/0x23a0
[  234.162505]  ? trace_event_raw_event_lock+0x190/0x190
[  234.162626]  __lock_acquire+0x129e/0x23a0
[  234.162746]  ? register_lock_class+0x8a0/0x8a0
[  234.162866]  lock_acquire+0xf3/0x210
[  234.162982]  ? kernfs_remove_by_name_ns+0x40/0x80
[  234.163127]  __kernfs_remove+0x42b/0x4c0
[  234.163243]  ? kernfs_remove_by_name_ns+0x40/0x80
[  234.163363]  ? kernfs_fop_readdir+0x3b0/0x3b0
[  234.163482]  ? strlen+0x1f/0x40
[  234.163596]  ? strcmp+0x30/0x50
[  234.163712]  kernfs_remove_by_name_ns+0x40/0x80
[  234.163832]  remove_files+0x3f/0xa0
[  234.163948]  sysfs_remove_group+0x4a/0xb0
[  234.164068]  rnbd_srv_destroy_dev_session_sysfs+0x19/0x30 [rnbd_server]
[  234.164196]  rnbd_srv_rdma_ev+0x14c/0x1590 [rnbd_server]
[  234.164345]  ? _raw_spin_unlock_irqrestore+0x43/0x50
[  234.164466]  ? lockdep_hardirqs_on+0x1a8/0x290
[  234.164597]  ? mlx4_ib_poll_cq+0x927/0x1280 [mlx4_ib]
[  234.164732]  ? rnbd_get_sess_dev+0x270/0x270 [rnbd_server]
[  234.164859]  process_io_req+0x29a/0x6a0 [rtrs_server]
[  234.164982]  ? rnbd_get_sess_dev+0x270/0x270 [rnbd_server]
[  234.165130]  __ib_process_cq+0x8c/0x100 [ib_core]
[  234.165279]  ib_cq_poll_work+0x31/0xb0 [ib_core]
[  234.165404]  process_one_work+0x4e5/0xaa0
[  234.165550]  ? pwq_dec_nr_in_flight+0x160/0x160
[  234.165675]  ? do_raw_spin_lock+0x119/0x1d0
[  234.165796]  worker_thread+0x65/0x5c0
[  234.165914]  ? process_one_work+0xaa0/0xaa0
[  234.166031]  kthread+0x1e0/0x200
[  234.166147]  ? kthread_create_worker_on_cpu+0xc0/0xc0
[  234.166268]  ret_from_fork+0x24/0x30
[  234.251591] rnbd_server L243: </dev/loop1@close_device_session>: Device closed
[  234.604221] rnbd_server L264: RTRS Session close_device_session disconnected

Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Signed-off-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Link: https://lore.kernel.org/r/20210419073722.15351-10-gi-oh.kim@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
esmil pushed a commit that referenced this pull request Sep 20, 2021
It's later supposed to be either a correct address or NULL. Without the
initialization, it may contain an undefined value which results in the
following segmentation fault:

  # perf top --sort comm -g --ignore-callees=do_idle

terminates with:

  #0  0x00007ffff56b7685 in __strlen_avx2 () from /lib64/libc.so.6
  #1  0x00007ffff55e3802 in strdup () from /lib64/libc.so.6
  #2  0x00005555558cb139 in hist_entry__init (callchain_size=<optimized out>, sample_self=true, template=0x7fffde7fb110, he=0x7fffd801c250) at util/hist.c:489
  #3  hist_entry__new (template=template@entry=0x7fffde7fb110, sample_self=sample_self@entry=true) at util/hist.c:564
  #4  0x00005555558cb4ba in hists__findnew_entry (hists=hists@entry=0x5555561d9e38, entry=entry@entry=0x7fffde7fb110, al=al@entry=0x7fffde7fb420,
      sample_self=sample_self@entry=true) at util/hist.c:657
  #5  0x00005555558cba1b in __hists__add_entry (hists=hists@entry=0x5555561d9e38, al=0x7fffde7fb420, sym_parent=<optimized out>, bi=bi@entry=0x0, mi=mi@entry=0x0,
      sample=sample@entry=0x7fffde7fb4b0, sample_self=true, ops=0x0, block_info=0x0) at util/hist.c:288
  #6  0x00005555558cbb70 in hists__add_entry (sample_self=true, sample=0x7fffde7fb4b0, mi=0x0, bi=0x0, sym_parent=<optimized out>, al=<optimized out>, hists=0x5555561d9e38)
      at util/hist.c:1056
  #7  iter_add_single_cumulative_entry (iter=0x7fffde7fb460, al=<optimized out>) at util/hist.c:1056
  #8  0x00005555558cc8a4 in hist_entry_iter__add (iter=iter@entry=0x7fffde7fb460, al=al@entry=0x7fffde7fb420, max_stack_depth=<optimized out>, arg=arg@entry=0x7fffffff7db0)
      at util/hist.c:1231
  #9  0x00005555557cdc9a in perf_event__process_sample (machine=<optimized out>, sample=0x7fffde7fb4b0, evsel=<optimized out>, event=<optimized out>, tool=0x7fffffff7db0)
      at builtin-top.c:842
  #10 deliver_event (qe=<optimized out>, qevent=<optimized out>) at builtin-top.c:1202
  #11 0x00005555558a9318 in do_flush (show_progress=false, oe=0x7fffffff80e0) at util/ordered-events.c:244
  #12 __ordered_events__flush (oe=oe@entry=0x7fffffff80e0, how=how@entry=OE_FLUSH__TOP, timestamp=timestamp@entry=0) at util/ordered-events.c:323
  #13 0x00005555558a9789 in __ordered_events__flush (timestamp=<optimized out>, how=<optimized out>, oe=<optimized out>) at util/ordered-events.c:339
  #14 ordered_events__flush (how=OE_FLUSH__TOP, oe=0x7fffffff80e0) at util/ordered-events.c:341
  #15 ordered_events__flush (oe=oe@entry=0x7fffffff80e0, how=how@entry=OE_FLUSH__TOP) at util/ordered-events.c:339
  #16 0x00005555557cd631 in process_thread (arg=0x7fffffff7db0) at builtin-top.c:1114
  #17 0x00007ffff7bb817a in start_thread () from /lib64/libpthread.so.0
  #18 0x00007ffff5656dc3 in clone () from /lib64/libc.so.6

If you look at the frame #2, the code is:

488	 if (he->srcline) {
489          he->srcline = strdup(he->srcline);
490          if (he->srcline == NULL)
491              goto err_rawdata;
492	 }

If he->srcline is not NULL (it is not NULL if it is uninitialized rubbish),
it gets strdupped and strdupping a rubbish random string causes the problem.

Also, if you look at the commit 1fb7d06, it adds the srcline property
into the struct, but not initializing it everywhere needed.

Committer notes:

Now I see, when using --ignore-callees=do_idle we end up here at line
2189 in add_callchain_ip():

2181         if (al.sym != NULL) {
2182                 if (perf_hpp_list.parent && !*parent &&
2183                     symbol__match_regex(al.sym, &parent_regex))
2184                         *parent = al.sym;
2185                 else if (have_ignore_callees && root_al &&
2186                   symbol__match_regex(al.sym, &ignore_callees_regex)) {
2187                         /* Treat this symbol as the root,
2188                            forgetting its callees. */
2189                         *root_al = al;
2190                         callchain_cursor_reset(cursor);
2191                 }
2192         }

And the al that doesn't have the ->srcline field initialized will be
copied to the root_al, so then, back to:

1211 int hist_entry_iter__add(struct hist_entry_iter *iter, struct addr_location *al,
1212                          int max_stack_depth, void *arg)
1213 {
1214         int err, err2;
1215         struct map *alm = NULL;
1216
1217         if (al)
1218                 alm = map__get(al->map);
1219
1220         err = sample__resolve_callchain(iter->sample, &callchain_cursor, &iter->parent,
1221                                         iter->evsel, al, max_stack_depth);
1222         if (err) {
1223                 map__put(alm);
1224                 return err;
1225         }
1226
1227         err = iter->ops->prepare_entry(iter, al);
1228         if (err)
1229                 goto out;
1230
1231         err = iter->ops->add_single_entry(iter, al);
1232         if (err)
1233                 goto out;
1234

That al at line 1221 is what hist_entry_iter__add() (called from
sample__resolve_callchain()) saw as 'root_al', and then:

        iter->ops->add_single_entry(iter, al);

will go on with al->srcline with a bogus value, I'll add the above
sequence to the cset and apply, thanks!

Signed-off-by: Michael Petlan <mpetlan@redhat.com>
CC: Milian Wolff <milian.wolff@kdab.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Fixes: 1fb7d06 ("perf report Use srcline from callchain for hist entries")
Link: https //lore.kernel.org/r/20210719145332.29747-1-mpetlan@redhat.com
Reported-by: Juri Lelli <jlelli@redhat.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
esmil pushed a commit that referenced this pull request Sep 20, 2021
FD uses xyarray__entry that may return NULL if an index is out of
bounds. If NULL is returned then a segv happens as FD unconditionally
dereferences the pointer. This was happening in a case of with perf
iostat as shown below. The fix is to make FD an "int*" rather than an
int and handle the NULL case as either invalid input or a closed fd.

  $ sudo gdb --args perf stat --iostat  list
  ...
  Breakpoint 1, perf_evsel__alloc_fd (evsel=0x5555560951a0, ncpus=1, nthreads=1) at evsel.c:50
  50      {
  (gdb) bt
   #0  perf_evsel__alloc_fd (evsel=0x5555560951a0, ncpus=1, nthreads=1) at evsel.c:50
   #1  0x000055555585c188 in evsel__open_cpu (evsel=0x5555560951a0, cpus=0x555556093410,
      threads=0x555556086fb0, start_cpu=0, end_cpu=1) at util/evsel.c:1792
   #2  0x000055555585cfb2 in evsel__open (evsel=0x5555560951a0, cpus=0x0, threads=0x555556086fb0)
      at util/evsel.c:2045
   #3  0x000055555585d0db in evsel__open_per_thread (evsel=0x5555560951a0, threads=0x555556086fb0)
      at util/evsel.c:2065
   #4  0x00005555558ece64 in create_perf_stat_counter (evsel=0x5555560951a0,
      config=0x555555c34700 <stat_config>, target=0x555555c2f1c0 <target>, cpu=0) at util/stat.c:590
   #5  0x000055555578e927 in __run_perf_stat (argc=1, argv=0x7fffffffe4a0, run_idx=0)
      at builtin-stat.c:833
   #6  0x000055555578f3c6 in run_perf_stat (argc=1, argv=0x7fffffffe4a0, run_idx=0)
      at builtin-stat.c:1048
   #7  0x0000555555792ee5 in cmd_stat (argc=1, argv=0x7fffffffe4a0) at builtin-stat.c:2534
   #8  0x0000555555835ed3 in run_builtin (p=0x555555c3f540 <commands+288>, argc=3,
      argv=0x7fffffffe4a0) at perf.c:313
   #9  0x0000555555836154 in handle_internal_command (argc=3, argv=0x7fffffffe4a0) at perf.c:365
   #10 0x000055555583629f in run_argv (argcp=0x7fffffffe2ec, argv=0x7fffffffe2e0) at perf.c:409
   #11 0x0000555555836692 in main (argc=3, argv=0x7fffffffe4a0) at perf.c:539
  ...
  (gdb) c
  Continuing.
  Error:
  The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (uncore_iio_0/event=0x83,umask=0x04,ch_mask=0xF,fc_mask=0x07/).
  /bin/dmesg | grep -i perf may provide additional information.

  Program received signal SIGSEGV, Segmentation fault.
  0x00005555559b03ea in perf_evsel__close_fd_cpu (evsel=0x5555560951a0, cpu=1) at evsel.c:166
  166                     if (FD(evsel, cpu, thread) >= 0)

v3. fixes a bug in perf_evsel__run_ioctl where the sense of a branch was
    backward.

Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20210918054440.2350466-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
esmil pushed a commit that referenced this pull request Sep 22, 2021
On SiFive Unmatched, I recently fell onto the following BUG when booting:

[    0.000000] ftrace: allocating 36610 entries in 144 pages
[    0.000000] Oops - illegal instruction [#1]
[    0.000000] Modules linked in:
[    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.13.1+ #5
[    0.000000] Hardware name: SiFive HiFive Unmatched A00 (DT)
[    0.000000] epc : riscv_cpuid_to_hartid_mask+0x6/0xae
[    0.000000]  ra : __sbi_rfence_v02+0xc8/0x10a
[    0.000000] epc : ffffffff80007240 ra : ffffffff80009964 sp : ffffffff81803e10
[    0.000000]  gp : ffffffff81a1ea70 tp : ffffffff8180f500 t0 : ffffffe07fe30000
[    0.000000]  t1 : 0000000000000004 t2 : 0000000000000000 s0 : ffffffff81803e60
[    0.000000]  s1 : 0000000000000000 a0 : ffffffff81a22238 a1 : ffffffff81803e10
[    0.000000]  a2 : 0000000000000000 a3 : 0000000000000000 a4 : 0000000000000000
[    0.000000]  a5 : 0000000000000000 a6 : ffffffff8000989c a7 : 0000000052464e43
[    0.000000]  s2 : ffffffff81a220c8 s3 : 0000000000000000 s4 : 0000000000000000
[    0.000000]  s5 : 0000000000000000 s6 : 0000000200000100 s7 : 0000000000000001
[    0.000000]  s8 : ffffffe07fe04040 s9 : ffffffff81a22c80 s10: 0000000000001000
[    0.000000]  s11: 0000000000000004 t3 : 0000000000000001 t4 : 0000000000000008
[    0.000000]  t5 : ffffffcf04000808 t6 : ffffffe3ffddf188
[    0.000000] status: 0000000200000100 badaddr: 0000000000000000 cause: 0000000000000002
[    0.000000] [<ffffffff80007240>] riscv_cpuid_to_hartid_mask+0x6/0xae
[    0.000000] [<ffffffff80009474>] sbi_remote_fence_i+0x1e/0x26
[    0.000000] [<ffffffff8000b8f4>] flush_icache_all+0x12/0x1a
[    0.000000] [<ffffffff8000666c>] patch_text_nosync+0x26/0x32
[    0.000000] [<ffffffff8000884e>] ftrace_init_nop+0x52/0x8c
[    0.000000] [<ffffffff800f051e>] ftrace_process_locs.isra.0+0x29c/0x360
[    0.000000] [<ffffffff80a0e3c6>] ftrace_init+0x80/0x130
[    0.000000] [<ffffffff80a00f8c>] start_kernel+0x5c4/0x8f6
[    0.000000] ---[ end trace f67eb9af4d8d492b ]---
[    0.000000] Kernel panic - not syncing: Attempted to kill the idle task!
[    0.000000] ---[ end Kernel panic - not syncing: Attempted to kill the idle task! ]---

While ftrace is looping over a list of addresses to patch, it always failed
when patching the same function: riscv_cpuid_to_hartid_mask. Looking at the
backtrace, the illegal instruction is encountered in this same function.
However, patch_text_nosync, after patching the instructions, calls
flush_icache_range. But looking at what happens in this function:

flush_icache_range -> flush_icache_all
                   -> sbi_remote_fence_i
                   -> __sbi_rfence_v02
                   -> riscv_cpuid_to_hartid_mask

The icache and dcache of the current cpu are never synchronized between the
patching of riscv_cpuid_to_hartid_mask and calling this same function.

So fix this by flushing the current cpu's icache before asking for the other
cpus to do the same.

Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
esmil pushed a commit that referenced this pull request Sep 22, 2021
Following test case reproduces lockdep warning.

  Test case:

  $ mkfs.btrfs -f <dev1>
  $ btrfstune -S 1 <dev1>
  $ mount <dev1> <mnt>
  $ btrfs device add <dev2> <mnt> -f
  $ umount <mnt>
  $ mount <dev2> <mnt>
  $ umount <mnt>

The warning claims a possible ABBA deadlock between the threads
initiated by [#1] btrfs device add and [#0] the mount.

  [ 540.743122] WARNING: possible circular locking dependency detected
  [ 540.743129] 5.11.0-rc7+ #5 Not tainted
  [ 540.743135] ------------------------------------------------------
  [ 540.743142] mount/2515 is trying to acquire lock:
  [ 540.743149] ffffa0c5544c2ce0 (&fs_devs->device_list_mutex){+.+.}-{4:4}, at: clone_fs_devices+0x6d/0x210 [btrfs]
  [ 540.743458] but task is already holding lock:
  [ 540.743461] ffffa0c54a7932b8 (btrfs-chunk-00){++++}-{4:4}, at: __btrfs_tree_read_lock+0x32/0x200 [btrfs]
  [ 540.743541] which lock already depends on the new lock.
  [ 540.743543] the existing dependency chain (in reverse order) is:

  [ 540.743546] -> #1 (btrfs-chunk-00){++++}-{4:4}:
  [ 540.743566] down_read_nested+0x48/0x2b0
  [ 540.743585] __btrfs_tree_read_lock+0x32/0x200 [btrfs]
  [ 540.743650] btrfs_read_lock_root_node+0x70/0x200 [btrfs]
  [ 540.743733] btrfs_search_slot+0x6c6/0xe00 [btrfs]
  [ 540.743785] btrfs_update_device+0x83/0x260 [btrfs]
  [ 540.743849] btrfs_finish_chunk_alloc+0x13f/0x660 [btrfs] <--- device_list_mutex
  [ 540.743911] btrfs_create_pending_block_groups+0x18d/0x3f0 [btrfs]
  [ 540.743982] btrfs_commit_transaction+0x86/0x1260 [btrfs]
  [ 540.744037] btrfs_init_new_device+0x1600/0x1dd0 [btrfs]
  [ 540.744101] btrfs_ioctl+0x1c77/0x24c0 [btrfs]
  [ 540.744166] __x64_sys_ioctl+0xe4/0x140
  [ 540.744170] do_syscall_64+0x4b/0x80
  [ 540.744174] entry_SYSCALL_64_after_hwframe+0x44/0xa9

  [ 540.744180] -> #0 (&fs_devs->device_list_mutex){+.+.}-{4:4}:
  [ 540.744184] __lock_acquire+0x155f/0x2360
  [ 540.744188] lock_acquire+0x10b/0x5c0
  [ 540.744190] __mutex_lock+0xb1/0xf80
  [ 540.744193] mutex_lock_nested+0x27/0x30
  [ 540.744196] clone_fs_devices+0x6d/0x210 [btrfs]
  [ 540.744270] btrfs_read_chunk_tree+0x3c7/0xbb0 [btrfs]
  [ 540.744336] open_ctree+0xf6e/0x2074 [btrfs]
  [ 540.744406] btrfs_mount_root.cold.72+0x16/0x127 [btrfs]
  [ 540.744472] legacy_get_tree+0x38/0x90
  [ 540.744475] vfs_get_tree+0x30/0x140
  [ 540.744478] fc_mount+0x16/0x60
  [ 540.744482] vfs_kern_mount+0x91/0x100
  [ 540.744484] btrfs_mount+0x1e6/0x670 [btrfs]
  [ 540.744536] legacy_get_tree+0x38/0x90
  [ 540.744537] vfs_get_tree+0x30/0x140
  [ 540.744539] path_mount+0x8d8/0x1070
  [ 540.744541] do_mount+0x8d/0xc0
  [ 540.744543] __x64_sys_mount+0x125/0x160
  [ 540.744545] do_syscall_64+0x4b/0x80
  [ 540.744547] entry_SYSCALL_64_after_hwframe+0x44/0xa9

  [ 540.744551] other info that might help us debug this:
  [ 540.744552] Possible unsafe locking scenario:

  [ 540.744553] CPU0 				CPU1
  [ 540.744554] ---- 				----
  [ 540.744555] lock(btrfs-chunk-00);
  [ 540.744557] 					lock(&fs_devs->device_list_mutex);
  [ 540.744560] 					lock(btrfs-chunk-00);
  [ 540.744562] lock(&fs_devs->device_list_mutex);
  [ 540.744564]
   *** DEADLOCK ***

  [ 540.744565] 3 locks held by mount/2515:
  [ 540.744567] #0: ffffa0c56bf7a0e0 (&type->s_umount_key#42/1){+.+.}-{4:4}, at: alloc_super.isra.16+0xdf/0x450
  [ 540.744574] #1: ffffffffc05a9628 (uuid_mutex){+.+.}-{4:4}, at: btrfs_read_chunk_tree+0x63/0xbb0 [btrfs]
  [ 540.744640] #2: ffffa0c54a7932b8 (btrfs-chunk-00){++++}-{4:4}, at: __btrfs_tree_read_lock+0x32/0x200 [btrfs]
  [ 540.744708]
   stack backtrace:
  [ 540.744712] CPU: 2 PID: 2515 Comm: mount Not tainted 5.11.0-rc7+ #5

But the device_list_mutex in clone_fs_devices() is redundant, as
explained below.  Two threads [1]  and [2] (below) could lead to
clone_fs_device().

  [1]
  open_ctree <== mount sprout fs
   btrfs_read_chunk_tree()
    mutex_lock(&uuid_mutex) <== global lock
    read_one_dev()
     open_seed_devices()
      clone_fs_devices() <== seed fs_devices
       mutex_lock(&orig->device_list_mutex) <== seed fs_devices

  [2]
  btrfs_init_new_device() <== sprouting
   mutex_lock(&uuid_mutex); <== global lock
   btrfs_prepare_sprout()
     lockdep_assert_held(&uuid_mutex)
     clone_fs_devices(seed_fs_device) <== seed fs_devices

Both of these threads hold uuid_mutex which is sufficient to protect
getting the seed device(s) freed while we are trying to clone it for
sprouting [2] or mounting a sprout [1] (as above). A mounted seed device
can not free/write/replace because it is read-only. An unmounted seed
device can be freed by btrfs_free_stale_devices(), but it needs
uuid_mutex.  So this patch removes the unnecessary device_list_mutex in
clone_fs_devices().  And adds a lockdep_assert_held(&uuid_mutex) in
clone_fs_devices().

Reported-by: Su Yue <l@damenly.su>
Tested-by: Su Yue <l@damenly.su>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
esmil pushed a commit that referenced this pull request Sep 22, 2021
If CONFIG_BLK_DEV_LOOP && CONFIG_MTD (at least; there might be other
combinations), lockdep complains circular locking dependency at
__loop_clr_fd(), for major_names_lock serves as a locking dependency
aggregating hub across multiple block modules.

 ======================================================
 WARNING: possible circular locking dependency detected
 5.14.0+ #757 Tainted: G            E
 ------------------------------------------------------
 systemd-udevd/7568 is trying to acquire lock:
 ffff88800f334d48 ((wq_completion)loop0){+.+.}-{0:0}, at: flush_workqueue+0x70/0x560

 but task is already holding lock:
 ffff888014a7d4a0 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x4d/0x400 [loop]

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #6 (&lo->lo_mutex){+.+.}-{3:3}:
        lock_acquire+0xbe/0x1f0
        __mutex_lock_common+0xb6/0xe10
        mutex_lock_killable_nested+0x17/0x20
        lo_open+0x23/0x50 [loop]
        blkdev_get_by_dev+0x199/0x540
        blkdev_open+0x58/0x90
        do_dentry_open+0x144/0x3a0
        path_openat+0xa57/0xda0
        do_filp_open+0x9f/0x140
        do_sys_openat2+0x71/0x150
        __x64_sys_openat+0x78/0xa0
        do_syscall_64+0x3d/0xb0
        entry_SYSCALL_64_after_hwframe+0x44/0xae

 -> #5 (&disk->open_mutex){+.+.}-{3:3}:
        lock_acquire+0xbe/0x1f0
        __mutex_lock_common+0xb6/0xe10
        mutex_lock_nested+0x17/0x20
        bd_register_pending_holders+0x20/0x100
        device_add_disk+0x1ae/0x390
        loop_add+0x29c/0x2d0 [loop]
        blk_request_module+0x5a/0xb0
        blkdev_get_no_open+0x27/0xa0
        blkdev_get_by_dev+0x5f/0x540
        blkdev_open+0x58/0x90
        do_dentry_open+0x144/0x3a0
        path_openat+0xa57/0xda0
        do_filp_open+0x9f/0x140
        do_sys_openat2+0x71/0x150
        __x64_sys_openat+0x78/0xa0
        do_syscall_64+0x3d/0xb0
        entry_SYSCALL_64_after_hwframe+0x44/0xae

 -> #4 (major_names_lock){+.+.}-{3:3}:
        lock_acquire+0xbe/0x1f0
        __mutex_lock_common+0xb6/0xe10
        mutex_lock_nested+0x17/0x20
        blkdev_show+0x19/0x80
        devinfo_show+0x52/0x60
        seq_read_iter+0x2d5/0x3e0
        proc_reg_read_iter+0x41/0x80
        vfs_read+0x2ac/0x330
        ksys_read+0x6b/0xd0
        do_syscall_64+0x3d/0xb0
        entry_SYSCALL_64_after_hwframe+0x44/0xae

 -> #3 (&p->lock){+.+.}-{3:3}:
        lock_acquire+0xbe/0x1f0
        __mutex_lock_common+0xb6/0xe10
        mutex_lock_nested+0x17/0x20
        seq_read_iter+0x37/0x3e0
        generic_file_splice_read+0xf3/0x170
        splice_direct_to_actor+0x14e/0x350
        do_splice_direct+0x84/0xd0
        do_sendfile+0x263/0x430
        __se_sys_sendfile64+0x96/0xc0
        do_syscall_64+0x3d/0xb0
        entry_SYSCALL_64_after_hwframe+0x44/0xae

 -> #2 (sb_writers#3){.+.+}-{0:0}:
        lock_acquire+0xbe/0x1f0
        lo_write_bvec+0x96/0x280 [loop]
        loop_process_work+0xa68/0xc10 [loop]
        process_one_work+0x293/0x480
        worker_thread+0x23d/0x4b0
        kthread+0x163/0x180
        ret_from_fork+0x1f/0x30

 -> #1 ((work_completion)(&lo->rootcg_work)){+.+.}-{0:0}:
        lock_acquire+0xbe/0x1f0
        process_one_work+0x280/0x480
        worker_thread+0x23d/0x4b0
        kthread+0x163/0x180
        ret_from_fork+0x1f/0x30

 -> #0 ((wq_completion)loop0){+.+.}-{0:0}:
        validate_chain+0x1f0d/0x33e0
        __lock_acquire+0x92d/0x1030
        lock_acquire+0xbe/0x1f0
        flush_workqueue+0x8c/0x560
        drain_workqueue+0x80/0x140
        destroy_workqueue+0x47/0x4f0
        __loop_clr_fd+0xb4/0x400 [loop]
        blkdev_put+0x14a/0x1d0
        blkdev_close+0x1c/0x20
        __fput+0xfd/0x220
        task_work_run+0x69/0xc0
        exit_to_user_mode_prepare+0x1ce/0x1f0
        syscall_exit_to_user_mode+0x26/0x60
        do_syscall_64+0x4c/0xb0
        entry_SYSCALL_64_after_hwframe+0x44/0xae

 other info that might help us debug this:

 Chain exists of:
   (wq_completion)loop0 --> &disk->open_mutex --> &lo->lo_mutex

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&lo->lo_mutex);
                                lock(&disk->open_mutex);
                                lock(&lo->lo_mutex);
   lock((wq_completion)loop0);

  *** DEADLOCK ***

 2 locks held by systemd-udevd/7568:
  #0: ffff888012554128 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0x4c/0x1d0
  #1: ffff888014a7d4a0 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x4d/0x400 [loop]

 stack backtrace:
 CPU: 0 PID: 7568 Comm: systemd-udevd Tainted: G            E     5.14.0+ #757
 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 02/27/2020
 Call Trace:
  dump_stack_lvl+0x79/0xbf
  print_circular_bug+0x5d6/0x5e0
  ? stack_trace_save+0x42/0x60
  ? save_trace+0x3d/0x2d0
  check_noncircular+0x10b/0x120
  validate_chain+0x1f0d/0x33e0
  ? __lock_acquire+0x953/0x1030
  ? __lock_acquire+0x953/0x1030
  __lock_acquire+0x92d/0x1030
  ? flush_workqueue+0x70/0x560
  lock_acquire+0xbe/0x1f0
  ? flush_workqueue+0x70/0x560
  flush_workqueue+0x8c/0x560
  ? flush_workqueue+0x70/0x560
  ? sched_clock_cpu+0xe/0x1a0
  ? drain_workqueue+0x41/0x140
  drain_workqueue+0x80/0x140
  destroy_workqueue+0x47/0x4f0
  ? blk_mq_freeze_queue_wait+0xac/0xd0
  __loop_clr_fd+0xb4/0x400 [loop]
  ? __mutex_unlock_slowpath+0x35/0x230
  blkdev_put+0x14a/0x1d0
  blkdev_close+0x1c/0x20
  __fput+0xfd/0x220
  task_work_run+0x69/0xc0
  exit_to_user_mode_prepare+0x1ce/0x1f0
  syscall_exit_to_user_mode+0x26/0x60
  do_syscall_64+0x4c/0xb0
  entry_SYSCALL_64_after_hwframe+0x44/0xae
 RIP: 0033:0x7f0fd4c661f7
 Code: 00 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 41 c3 48 83 ec 18 89 7c 24 0c e8 13 fc ff ff
 RSP: 002b:00007ffd1c9e9fd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
 RAX: 0000000000000000 RBX: 00007f0fd46be6c8 RCX: 00007f0fd4c661f7
 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006
 RBP: 0000000000000006 R08: 000055fff1eaf400 R09: 0000000000000000
 R10: 00007f0fd46be6c8 R11: 0000000000000246 R12: 0000000000000000
 R13: 0000000000000000 R14: 0000000000002f08 R15: 00007ffd1c9ea050

Commit 1c500ad ("loop: reduce the loop_ctl_mutex scope") is for
breaking "loop_ctl_mutex => &lo->lo_mutex" dependency chain. But enabling
a different block module results in forming circular locking dependency
due to shared major_names_lock mutex.

The simplest fix is to call probe function without holding
major_names_lock [1], but Christoph Hellwig does not like such idea.
Therefore, instead of holding major_names_lock in blkdev_show(),
introduce a different lock for blkdev_show() in order to break
"sb_writers#$N => &p->lock => major_names_lock" dependency chain.

Link: https://lkml.kernel.org/r/b2af8a5b-3c1b-204e-7f56-bea0b15848d6@i-love.sakura.ne.jp [1]
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Link: https://lore.kernel.org/r/18a02da2-0bf3-550e-b071-2b4ab13c49f0@i-love.sakura.ne.jp
Signed-off-by: Jens Axboe <axboe@kernel.dk>
esmil pushed a commit that referenced this pull request Sep 24, 2021
commit 13be2ef upstream.

As previously noted in commit 66e4f4a ("rtc: cmos: Use
spin_lock_irqsave() in cmos_interrupt()"):

<4>[  254.192378] WARNING: inconsistent lock state
<4>[  254.192384] 5.12.0-rc1-CI-CI_DRM_9834+ #1 Not tainted
<4>[  254.192396] --------------------------------
<4>[  254.192400] inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
<4>[  254.192409] rtcwake/5309 [HC0[0]:SC0[0]:HE1:SE1] takes:
<4>[  254.192429] ffffffff8263c5f8 (rtc_lock){?...}-{2:2}, at: cmos_interrupt+0x18/0x100
<4>[  254.192481] {IN-HARDIRQ-W} state was registered at:
<4>[  254.192488]   lock_acquire+0xd1/0x3d0
<4>[  254.192504]   _raw_spin_lock+0x2a/0x40
<4>[  254.192519]   cmos_interrupt+0x18/0x100
<4>[  254.192536]   rtc_handler+0x1f/0xc0
<4>[  254.192553]   acpi_ev_fixed_event_detect+0x109/0x13c
<4>[  254.192574]   acpi_ev_sci_xrupt_handler+0xb/0x28
<4>[  254.192596]   acpi_irq+0x13/0x30
<4>[  254.192620]   __handle_irq_event_percpu+0x43/0x2c0
<4>[  254.192641]   handle_irq_event_percpu+0x2b/0x70
<4>[  254.192661]   handle_irq_event+0x2f/0x50
<4>[  254.192680]   handle_fasteoi_irq+0x9e/0x150
<4>[  254.192693]   __common_interrupt+0x76/0x140
<4>[  254.192715]   common_interrupt+0x96/0xc0
<4>[  254.192732]   asm_common_interrupt+0x1e/0x40
<4>[  254.192750]   _raw_spin_unlock_irqrestore+0x38/0x60
<4>[  254.192767]   resume_irqs+0xba/0xf0
<4>[  254.192786]   dpm_resume_noirq+0x245/0x3d0
<4>[  254.192811]   suspend_devices_and_enter+0x230/0xaa0
<4>[  254.192835]   pm_suspend.cold.8+0x301/0x34a
<4>[  254.192859]   state_store+0x7b/0xe0
<4>[  254.192879]   kernfs_fop_write_iter+0x11d/0x1c0
<4>[  254.192899]   new_sync_write+0x11d/0x1b0
<4>[  254.192916]   vfs_write+0x265/0x390
<4>[  254.192933]   ksys_write+0x5a/0xd0
<4>[  254.192949]   do_syscall_64+0x33/0x80
<4>[  254.192965]   entry_SYSCALL_64_after_hwframe+0x44/0xae
<4>[  254.192986] irq event stamp: 43775
<4>[  254.192994] hardirqs last  enabled at (43775): [<ffffffff81c00c42>] asm_sysvec_apic_timer_interrupt+0x12/0x20
<4>[  254.193023] hardirqs last disabled at (43774): [<ffffffff81aa691a>] sysvec_apic_timer_interrupt+0xa/0xb0
<4>[  254.193049] softirqs last  enabled at (42548): [<ffffffff81e00342>] __do_softirq+0x342/0x48e
<4>[  254.193074] softirqs last disabled at (42543): [<ffffffff810b45fd>] irq_exit_rcu+0xad/0xd0
<4>[  254.193101]
                  other info that might help us debug this:
<4>[  254.193107]  Possible unsafe locking scenario:

<4>[  254.193112]        CPU0
<4>[  254.193117]        ----
<4>[  254.193121]   lock(rtc_lock);
<4>[  254.193137]   <Interrupt>
<4>[  254.193142]     lock(rtc_lock);
<4>[  254.193156]
                   *** DEADLOCK ***

<4>[  254.193161] 6 locks held by rtcwake/5309:
<4>[  254.193174]  #0: ffff888104861430 (sb_writers#5){.+.+}-{0:0}, at: ksys_write+0x5a/0xd0
<4>[  254.193232]  #1: ffff88810f823288 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0xe7/0x1c0
<4>[  254.193282]  #2: ffff888100cef3c0 (kn->active#285
<7>[  254.192706] i915 0000:00:02.0: [drm:intel_modeset_setup_hw_state [i915]] [CRTC:51:pipe A] hw state readout: disabled
<4>[  254.193307] ){.+.+}-{0:0}, at: kernfs_fop_write_iter+0xf0/0x1c0
<4>[  254.193333]  #3: ffffffff82649fa8 (system_transition_mutex){+.+.}-{3:3}, at: pm_suspend.cold.8+0xce/0x34a
<4>[  254.193387]  #4: ffffffff827a2108 (acpi_scan_lock){+.+.}-{3:3}, at: acpi_suspend_begin+0x47/0x70
<4>[  254.193433]  #5: ffff8881019ea178 (&dev->mutex){....}-{3:3}, at: device_resume+0x68/0x1e0
<4>[  254.193485]
                  stack backtrace:
<4>[  254.193492] CPU: 1 PID: 5309 Comm: rtcwake Not tainted 5.12.0-rc1-CI-CI_DRM_9834+ #1
<4>[  254.193514] Hardware name: Google Soraka/Soraka, BIOS MrChromebox-4.10 08/25/2019
<4>[  254.193524] Call Trace:
<4>[  254.193536]  dump_stack+0x7f/0xad
<4>[  254.193567]  mark_lock.part.47+0x8ca/0xce0
<4>[  254.193604]  __lock_acquire+0x39b/0x2590
<4>[  254.193626]  ? asm_sysvec_apic_timer_interrupt+0x12/0x20
<4>[  254.193660]  lock_acquire+0xd1/0x3d0
<4>[  254.193677]  ? cmos_interrupt+0x18/0x100
<4>[  254.193716]  _raw_spin_lock+0x2a/0x40
<4>[  254.193735]  ? cmos_interrupt+0x18/0x100
<4>[  254.193758]  cmos_interrupt+0x18/0x100
<4>[  254.193785]  cmos_resume+0x2ac/0x2d0
<4>[  254.193813]  ? acpi_pm_set_device_wakeup+0x1f/0x110
<4>[  254.193842]  ? pnp_bus_suspend+0x10/0x10
<4>[  254.193864]  pnp_bus_resume+0x5e/0x90
<4>[  254.193885]  dpm_run_callback+0x5f/0x240
<4>[  254.193914]  device_resume+0xb2/0x1e0
<4>[  254.193942]  ? pm_dev_err+0x25/0x25
<4>[  254.193974]  dpm_resume+0xea/0x3f0
<4>[  254.194005]  dpm_resume_end+0x8/0x10
<4>[  254.194030]  suspend_devices_and_enter+0x29b/0xaa0
<4>[  254.194066]  pm_suspend.cold.8+0x301/0x34a
<4>[  254.194094]  state_store+0x7b/0xe0
<4>[  254.194124]  kernfs_fop_write_iter+0x11d/0x1c0
<4>[  254.194151]  new_sync_write+0x11d/0x1b0
<4>[  254.194183]  vfs_write+0x265/0x390
<4>[  254.194207]  ksys_write+0x5a/0xd0
<4>[  254.194232]  do_syscall_64+0x33/0x80
<4>[  254.194251]  entry_SYSCALL_64_after_hwframe+0x44/0xae
<4>[  254.194274] RIP: 0033:0x7f07d79691e7
<4>[  254.194293] Code: 64 89 02 48 c7 c0 ff ff ff ff eb bb 0f 1f 80 00 00 00 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24
<4>[  254.194312] RSP: 002b:00007ffd9cc2c768 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
<4>[  254.194337] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f07d79691e7
<4>[  254.194352] RDX: 0000000000000004 RSI: 0000556ebfc63590 RDI: 000000000000000b
<4>[  254.194366] RBP: 0000556ebfc63590 R08: 0000000000000000 R09: 0000000000000004
<4>[  254.194379] R10: 0000556ebf0ec2a6 R11: 0000000000000246 R12: 0000000000000004

which breaks S3-resume on fi-kbl-soraka presumably as that's slow enough
to trigger the alarm during the suspend.

Fixes: 6950d04 ("rtc: cmos: Replace spin_lock_irqsave with spin_lock in hard IRQ")
References: 66e4f4a ("rtc: cmos: Use spin_lock_irqsave() in cmos_interrupt()"):
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Xiaofei Tan <tanxiaofei@huawei.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20210305122140.28774-1-chris@chris-wilson.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
esmil pushed a commit that referenced this pull request Sep 24, 2021
commit 57f0ff0 upstream.

It's later supposed to be either a correct address or NULL. Without the
initialization, it may contain an undefined value which results in the
following segmentation fault:

  # perf top --sort comm -g --ignore-callees=do_idle

terminates with:

  #0  0x00007ffff56b7685 in __strlen_avx2 () from /lib64/libc.so.6
  #1  0x00007ffff55e3802 in strdup () from /lib64/libc.so.6
  #2  0x00005555558cb139 in hist_entry__init (callchain_size=<optimized out>, sample_self=true, template=0x7fffde7fb110, he=0x7fffd801c250) at util/hist.c:489
  #3  hist_entry__new (template=template@entry=0x7fffde7fb110, sample_self=sample_self@entry=true) at util/hist.c:564
  #4  0x00005555558cb4ba in hists__findnew_entry (hists=hists@entry=0x5555561d9e38, entry=entry@entry=0x7fffde7fb110, al=al@entry=0x7fffde7fb420,
      sample_self=sample_self@entry=true) at util/hist.c:657
  #5  0x00005555558cba1b in __hists__add_entry (hists=hists@entry=0x5555561d9e38, al=0x7fffde7fb420, sym_parent=<optimized out>, bi=bi@entry=0x0, mi=mi@entry=0x0,
      sample=sample@entry=0x7fffde7fb4b0, sample_self=true, ops=0x0, block_info=0x0) at util/hist.c:288
  #6  0x00005555558cbb70 in hists__add_entry (sample_self=true, sample=0x7fffde7fb4b0, mi=0x0, bi=0x0, sym_parent=<optimized out>, al=<optimized out>, hists=0x5555561d9e38)
      at util/hist.c:1056
  #7  iter_add_single_cumulative_entry (iter=0x7fffde7fb460, al=<optimized out>) at util/hist.c:1056
  #8  0x00005555558cc8a4 in hist_entry_iter__add (iter=iter@entry=0x7fffde7fb460, al=al@entry=0x7fffde7fb420, max_stack_depth=<optimized out>, arg=arg@entry=0x7fffffff7db0)
      at util/hist.c:1231
  #9  0x00005555557cdc9a in perf_event__process_sample (machine=<optimized out>, sample=0x7fffde7fb4b0, evsel=<optimized out>, event=<optimized out>, tool=0x7fffffff7db0)
      at builtin-top.c:842
  #10 deliver_event (qe=<optimized out>, qevent=<optimized out>) at builtin-top.c:1202
  #11 0x00005555558a9318 in do_flush (show_progress=false, oe=0x7fffffff80e0) at util/ordered-events.c:244
  #12 __ordered_events__flush (oe=oe@entry=0x7fffffff80e0, how=how@entry=OE_FLUSH__TOP, timestamp=timestamp@entry=0) at util/ordered-events.c:323
  #13 0x00005555558a9789 in __ordered_events__flush (timestamp=<optimized out>, how=<optimized out>, oe=<optimized out>) at util/ordered-events.c:339
  #14 ordered_events__flush (how=OE_FLUSH__TOP, oe=0x7fffffff80e0) at util/ordered-events.c:341
  #15 ordered_events__flush (oe=oe@entry=0x7fffffff80e0, how=how@entry=OE_FLUSH__TOP) at util/ordered-events.c:339
  #16 0x00005555557cd631 in process_thread (arg=0x7fffffff7db0) at builtin-top.c:1114
  #17 0x00007ffff7bb817a in start_thread () from /lib64/libpthread.so.0
  #18 0x00007ffff5656dc3 in clone () from /lib64/libc.so.6

If you look at the frame #2, the code is:

488	 if (he->srcline) {
489          he->srcline = strdup(he->srcline);
490          if (he->srcline == NULL)
491              goto err_rawdata;
492	 }

If he->srcline is not NULL (it is not NULL if it is uninitialized rubbish),
it gets strdupped and strdupping a rubbish random string causes the problem.

Also, if you look at the commit 1fb7d06, it adds the srcline property
into the struct, but not initializing it everywhere needed.

Committer notes:

Now I see, when using --ignore-callees=do_idle we end up here at line
2189 in add_callchain_ip():

2181         if (al.sym != NULL) {
2182                 if (perf_hpp_list.parent && !*parent &&
2183                     symbol__match_regex(al.sym, &parent_regex))
2184                         *parent = al.sym;
2185                 else if (have_ignore_callees && root_al &&
2186                   symbol__match_regex(al.sym, &ignore_callees_regex)) {
2187                         /* Treat this symbol as the root,
2188                            forgetting its callees. */
2189                         *root_al = al;
2190                         callchain_cursor_reset(cursor);
2191                 }
2192         }

And the al that doesn't have the ->srcline field initialized will be
copied to the root_al, so then, back to:

1211 int hist_entry_iter__add(struct hist_entry_iter *iter, struct addr_location *al,
1212                          int max_stack_depth, void *arg)
1213 {
1214         int err, err2;
1215         struct map *alm = NULL;
1216
1217         if (al)
1218                 alm = map__get(al->map);
1219
1220         err = sample__resolve_callchain(iter->sample, &callchain_cursor, &iter->parent,
1221                                         iter->evsel, al, max_stack_depth);
1222         if (err) {
1223                 map__put(alm);
1224                 return err;
1225         }
1226
1227         err = iter->ops->prepare_entry(iter, al);
1228         if (err)
1229                 goto out;
1230
1231         err = iter->ops->add_single_entry(iter, al);
1232         if (err)
1233                 goto out;
1234

That al at line 1221 is what hist_entry_iter__add() (called from
sample__resolve_callchain()) saw as 'root_al', and then:

        iter->ops->add_single_entry(iter, al);

will go on with al->srcline with a bogus value, I'll add the above
sequence to the cset and apply, thanks!

Signed-off-by: Michael Petlan <mpetlan@redhat.com>
CC: Milian Wolff <milian.wolff@kdab.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Fixes: 1fb7d06 ("perf report Use srcline from callchain for hist entries")
Link: https //lore.kernel.org/r/20210719145332.29747-1-mpetlan@redhat.com
Reported-by: Juri Lelli <jlelli@redhat.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
esmil pushed a commit that referenced this pull request Sep 24, 2021
On SiFive Unmatched, I recently fell onto the following BUG when booting:

[    0.000000] ftrace: allocating 36610 entries in 144 pages
[    0.000000] Oops - illegal instruction [#1]
[    0.000000] Modules linked in:
[    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.13.1+ #5
[    0.000000] Hardware name: SiFive HiFive Unmatched A00 (DT)
[    0.000000] epc : riscv_cpuid_to_hartid_mask+0x6/0xae
[    0.000000]  ra : __sbi_rfence_v02+0xc8/0x10a
[    0.000000] epc : ffffffff80007240 ra : ffffffff80009964 sp : ffffffff81803e10
[    0.000000]  gp : ffffffff81a1ea70 tp : ffffffff8180f500 t0 : ffffffe07fe30000
[    0.000000]  t1 : 0000000000000004 t2 : 0000000000000000 s0 : ffffffff81803e60
[    0.000000]  s1 : 0000000000000000 a0 : ffffffff81a22238 a1 : ffffffff81803e10
[    0.000000]  a2 : 0000000000000000 a3 : 0000000000000000 a4 : 0000000000000000
[    0.000000]  a5 : 0000000000000000 a6 : ffffffff8000989c a7 : 0000000052464e43
[    0.000000]  s2 : ffffffff81a220c8 s3 : 0000000000000000 s4 : 0000000000000000
[    0.000000]  s5 : 0000000000000000 s6 : 0000000200000100 s7 : 0000000000000001
[    0.000000]  s8 : ffffffe07fe04040 s9 : ffffffff81a22c80 s10: 0000000000001000
[    0.000000]  s11: 0000000000000004 t3 : 0000000000000001 t4 : 0000000000000008
[    0.000000]  t5 : ffffffcf04000808 t6 : ffffffe3ffddf188
[    0.000000] status: 0000000200000100 badaddr: 0000000000000000 cause: 0000000000000002
[    0.000000] [<ffffffff80007240>] riscv_cpuid_to_hartid_mask+0x6/0xae
[    0.000000] [<ffffffff80009474>] sbi_remote_fence_i+0x1e/0x26
[    0.000000] [<ffffffff8000b8f4>] flush_icache_all+0x12/0x1a
[    0.000000] [<ffffffff8000666c>] patch_text_nosync+0x26/0x32
[    0.000000] [<ffffffff8000884e>] ftrace_init_nop+0x52/0x8c
[    0.000000] [<ffffffff800f051e>] ftrace_process_locs.isra.0+0x29c/0x360
[    0.000000] [<ffffffff80a0e3c6>] ftrace_init+0x80/0x130
[    0.000000] [<ffffffff80a00f8c>] start_kernel+0x5c4/0x8f6
[    0.000000] ---[ end trace f67eb9af4d8d492b ]---
[    0.000000] Kernel panic - not syncing: Attempted to kill the idle task!
[    0.000000] ---[ end Kernel panic - not syncing: Attempted to kill the idle task! ]---

While ftrace is looping over a list of addresses to patch, it always failed
when patching the same function: riscv_cpuid_to_hartid_mask. Looking at the
backtrace, the illegal instruction is encountered in this same function.
However, patch_text_nosync, after patching the instructions, calls
flush_icache_range. But looking at what happens in this function:

flush_icache_range -> flush_icache_all
                   -> sbi_remote_fence_i
                   -> __sbi_rfence_v02
                   -> riscv_cpuid_to_hartid_mask

The icache and dcache of the current cpu are never synchronized between the
patching of riscv_cpuid_to_hartid_mask and calling this same function.

So fix this by flushing the current cpu's icache before asking for the other
cpus to do the same.

Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
esmil pushed a commit that referenced this pull request Sep 26, 2021
[ Upstream commit c124706 ]

Following test case reproduces lockdep warning.

  Test case:

  $ mkfs.btrfs -f <dev1>
  $ btrfstune -S 1 <dev1>
  $ mount <dev1> <mnt>
  $ btrfs device add <dev2> <mnt> -f
  $ umount <mnt>
  $ mount <dev2> <mnt>
  $ umount <mnt>

The warning claims a possible ABBA deadlock between the threads
initiated by [#1] btrfs device add and [#0] the mount.

  [ 540.743122] WARNING: possible circular locking dependency detected
  [ 540.743129] 5.11.0-rc7+ #5 Not tainted
  [ 540.743135] ------------------------------------------------------
  [ 540.743142] mount/2515 is trying to acquire lock:
  [ 540.743149] ffffa0c5544c2ce0 (&fs_devs->device_list_mutex){+.+.}-{4:4}, at: clone_fs_devices+0x6d/0x210 [btrfs]
  [ 540.743458] but task is already holding lock:
  [ 540.743461] ffffa0c54a7932b8 (btrfs-chunk-00){++++}-{4:4}, at: __btrfs_tree_read_lock+0x32/0x200 [btrfs]
  [ 540.743541] which lock already depends on the new lock.
  [ 540.743543] the existing dependency chain (in reverse order) is:

  [ 540.743546] -> #1 (btrfs-chunk-00){++++}-{4:4}:
  [ 540.743566] down_read_nested+0x48/0x2b0
  [ 540.743585] __btrfs_tree_read_lock+0x32/0x200 [btrfs]
  [ 540.743650] btrfs_read_lock_root_node+0x70/0x200 [btrfs]
  [ 540.743733] btrfs_search_slot+0x6c6/0xe00 [btrfs]
  [ 540.743785] btrfs_update_device+0x83/0x260 [btrfs]
  [ 540.743849] btrfs_finish_chunk_alloc+0x13f/0x660 [btrfs] <--- device_list_mutex
  [ 540.743911] btrfs_create_pending_block_groups+0x18d/0x3f0 [btrfs]
  [ 540.743982] btrfs_commit_transaction+0x86/0x1260 [btrfs]
  [ 540.744037] btrfs_init_new_device+0x1600/0x1dd0 [btrfs]
  [ 540.744101] btrfs_ioctl+0x1c77/0x24c0 [btrfs]
  [ 540.744166] __x64_sys_ioctl+0xe4/0x140
  [ 540.744170] do_syscall_64+0x4b/0x80
  [ 540.744174] entry_SYSCALL_64_after_hwframe+0x44/0xa9

  [ 540.744180] -> #0 (&fs_devs->device_list_mutex){+.+.}-{4:4}:
  [ 540.744184] __lock_acquire+0x155f/0x2360
  [ 540.744188] lock_acquire+0x10b/0x5c0
  [ 540.744190] __mutex_lock+0xb1/0xf80
  [ 540.744193] mutex_lock_nested+0x27/0x30
  [ 540.744196] clone_fs_devices+0x6d/0x210 [btrfs]
  [ 540.744270] btrfs_read_chunk_tree+0x3c7/0xbb0 [btrfs]
  [ 540.744336] open_ctree+0xf6e/0x2074 [btrfs]
  [ 540.744406] btrfs_mount_root.cold.72+0x16/0x127 [btrfs]
  [ 540.744472] legacy_get_tree+0x38/0x90
  [ 540.744475] vfs_get_tree+0x30/0x140
  [ 540.744478] fc_mount+0x16/0x60
  [ 540.744482] vfs_kern_mount+0x91/0x100
  [ 540.744484] btrfs_mount+0x1e6/0x670 [btrfs]
  [ 540.744536] legacy_get_tree+0x38/0x90
  [ 540.744537] vfs_get_tree+0x30/0x140
  [ 540.744539] path_mount+0x8d8/0x1070
  [ 540.744541] do_mount+0x8d/0xc0
  [ 540.744543] __x64_sys_mount+0x125/0x160
  [ 540.744545] do_syscall_64+0x4b/0x80
  [ 540.744547] entry_SYSCALL_64_after_hwframe+0x44/0xa9

  [ 540.744551] other info that might help us debug this:
  [ 540.744552] Possible unsafe locking scenario:

  [ 540.744553] CPU0 				CPU1
  [ 540.744554] ---- 				----
  [ 540.744555] lock(btrfs-chunk-00);
  [ 540.744557] 					lock(&fs_devs->device_list_mutex);
  [ 540.744560] 					lock(btrfs-chunk-00);
  [ 540.744562] lock(&fs_devs->device_list_mutex);
  [ 540.744564]
   *** DEADLOCK ***

  [ 540.744565] 3 locks held by mount/2515:
  [ 540.744567] #0: ffffa0c56bf7a0e0 (&type->s_umount_key#42/1){+.+.}-{4:4}, at: alloc_super.isra.16+0xdf/0x450
  [ 540.744574] #1: ffffffffc05a9628 (uuid_mutex){+.+.}-{4:4}, at: btrfs_read_chunk_tree+0x63/0xbb0 [btrfs]
  [ 540.744640] #2: ffffa0c54a7932b8 (btrfs-chunk-00){++++}-{4:4}, at: __btrfs_tree_read_lock+0x32/0x200 [btrfs]
  [ 540.744708]
   stack backtrace:
  [ 540.744712] CPU: 2 PID: 2515 Comm: mount Not tainted 5.11.0-rc7+ #5

But the device_list_mutex in clone_fs_devices() is redundant, as
explained below.  Two threads [1]  and [2] (below) could lead to
clone_fs_device().

  [1]
  open_ctree <== mount sprout fs
   btrfs_read_chunk_tree()
    mutex_lock(&uuid_mutex) <== global lock
    read_one_dev()
     open_seed_devices()
      clone_fs_devices() <== seed fs_devices
       mutex_lock(&orig->device_list_mutex) <== seed fs_devices

  [2]
  btrfs_init_new_device() <== sprouting
   mutex_lock(&uuid_mutex); <== global lock
   btrfs_prepare_sprout()
     lockdep_assert_held(&uuid_mutex)
     clone_fs_devices(seed_fs_device) <== seed fs_devices

Both of these threads hold uuid_mutex which is sufficient to protect
getting the seed device(s) freed while we are trying to clone it for
sprouting [2] or mounting a sprout [1] (as above). A mounted seed device
can not free/write/replace because it is read-only. An unmounted seed
device can be freed by btrfs_free_stale_devices(), but it needs
uuid_mutex.  So this patch removes the unnecessary device_list_mutex in
clone_fs_devices().  And adds a lockdep_assert_held(&uuid_mutex) in
clone_fs_devices().

Reported-by: Su Yue <l@damenly.su>
Tested-by: Su Yue <l@damenly.su>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
esmil pushed a commit that referenced this pull request Sep 26, 2021
[ Upstream commit dfbb340 ]

If CONFIG_BLK_DEV_LOOP && CONFIG_MTD (at least; there might be other
combinations), lockdep complains circular locking dependency at
__loop_clr_fd(), for major_names_lock serves as a locking dependency
aggregating hub across multiple block modules.

 ======================================================
 WARNING: possible circular locking dependency detected
 5.14.0+ #757 Tainted: G            E
 ------------------------------------------------------
 systemd-udevd/7568 is trying to acquire lock:
 ffff88800f334d48 ((wq_completion)loop0){+.+.}-{0:0}, at: flush_workqueue+0x70/0x560

 but task is already holding lock:
 ffff888014a7d4a0 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x4d/0x400 [loop]

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #6 (&lo->lo_mutex){+.+.}-{3:3}:
        lock_acquire+0xbe/0x1f0
        __mutex_lock_common+0xb6/0xe10
        mutex_lock_killable_nested+0x17/0x20
        lo_open+0x23/0x50 [loop]
        blkdev_get_by_dev+0x199/0x540
        blkdev_open+0x58/0x90
        do_dentry_open+0x144/0x3a0
        path_openat+0xa57/0xda0
        do_filp_open+0x9f/0x140
        do_sys_openat2+0x71/0x150
        __x64_sys_openat+0x78/0xa0
        do_syscall_64+0x3d/0xb0
        entry_SYSCALL_64_after_hwframe+0x44/0xae

 -> #5 (&disk->open_mutex){+.+.}-{3:3}:
        lock_acquire+0xbe/0x1f0
        __mutex_lock_common+0xb6/0xe10
        mutex_lock_nested+0x17/0x20
        bd_register_pending_holders+0x20/0x100
        device_add_disk+0x1ae/0x390
        loop_add+0x29c/0x2d0 [loop]
        blk_request_module+0x5a/0xb0
        blkdev_get_no_open+0x27/0xa0
        blkdev_get_by_dev+0x5f/0x540
        blkdev_open+0x58/0x90
        do_dentry_open+0x144/0x3a0
        path_openat+0xa57/0xda0
        do_filp_open+0x9f/0x140
        do_sys_openat2+0x71/0x150
        __x64_sys_openat+0x78/0xa0
        do_syscall_64+0x3d/0xb0
        entry_SYSCALL_64_after_hwframe+0x44/0xae

 -> #4 (major_names_lock){+.+.}-{3:3}:
        lock_acquire+0xbe/0x1f0
        __mutex_lock_common+0xb6/0xe10
        mutex_lock_nested+0x17/0x20
        blkdev_show+0x19/0x80
        devinfo_show+0x52/0x60
        seq_read_iter+0x2d5/0x3e0
        proc_reg_read_iter+0x41/0x80
        vfs_read+0x2ac/0x330
        ksys_read+0x6b/0xd0
        do_syscall_64+0x3d/0xb0
        entry_SYSCALL_64_after_hwframe+0x44/0xae

 -> #3 (&p->lock){+.+.}-{3:3}:
        lock_acquire+0xbe/0x1f0
        __mutex_lock_common+0xb6/0xe10
        mutex_lock_nested+0x17/0x20
        seq_read_iter+0x37/0x3e0
        generic_file_splice_read+0xf3/0x170
        splice_direct_to_actor+0x14e/0x350
        do_splice_direct+0x84/0xd0
        do_sendfile+0x263/0x430
        __se_sys_sendfile64+0x96/0xc0
        do_syscall_64+0x3d/0xb0
        entry_SYSCALL_64_after_hwframe+0x44/0xae

 -> #2 (sb_writers#3){.+.+}-{0:0}:
        lock_acquire+0xbe/0x1f0
        lo_write_bvec+0x96/0x280 [loop]
        loop_process_work+0xa68/0xc10 [loop]
        process_one_work+0x293/0x480
        worker_thread+0x23d/0x4b0
        kthread+0x163/0x180
        ret_from_fork+0x1f/0x30

 -> #1 ((work_completion)(&lo->rootcg_work)){+.+.}-{0:0}:
        lock_acquire+0xbe/0x1f0
        process_one_work+0x280/0x480
        worker_thread+0x23d/0x4b0
        kthread+0x163/0x180
        ret_from_fork+0x1f/0x30

 -> #0 ((wq_completion)loop0){+.+.}-{0:0}:
        validate_chain+0x1f0d/0x33e0
        __lock_acquire+0x92d/0x1030
        lock_acquire+0xbe/0x1f0
        flush_workqueue+0x8c/0x560
        drain_workqueue+0x80/0x140
        destroy_workqueue+0x47/0x4f0
        __loop_clr_fd+0xb4/0x400 [loop]
        blkdev_put+0x14a/0x1d0
        blkdev_close+0x1c/0x20
        __fput+0xfd/0x220
        task_work_run+0x69/0xc0
        exit_to_user_mode_prepare+0x1ce/0x1f0
        syscall_exit_to_user_mode+0x26/0x60
        do_syscall_64+0x4c/0xb0
        entry_SYSCALL_64_after_hwframe+0x44/0xae

 other info that might help us debug this:

 Chain exists of:
   (wq_completion)loop0 --> &disk->open_mutex --> &lo->lo_mutex

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&lo->lo_mutex);
                                lock(&disk->open_mutex);
                                lock(&lo->lo_mutex);
   lock((wq_completion)loop0);

  *** DEADLOCK ***

 2 locks held by systemd-udevd/7568:
  #0: ffff888012554128 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0x4c/0x1d0
  #1: ffff888014a7d4a0 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x4d/0x400 [loop]

 stack backtrace:
 CPU: 0 PID: 7568 Comm: systemd-udevd Tainted: G            E     5.14.0+ #757
 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 02/27/2020
 Call Trace:
  dump_stack_lvl+0x79/0xbf
  print_circular_bug+0x5d6/0x5e0
  ? stack_trace_save+0x42/0x60
  ? save_trace+0x3d/0x2d0
  check_noncircular+0x10b/0x120
  validate_chain+0x1f0d/0x33e0
  ? __lock_acquire+0x953/0x1030
  ? __lock_acquire+0x953/0x1030
  __lock_acquire+0x92d/0x1030
  ? flush_workqueue+0x70/0x560
  lock_acquire+0xbe/0x1f0
  ? flush_workqueue+0x70/0x560
  flush_workqueue+0x8c/0x560
  ? flush_workqueue+0x70/0x560
  ? sched_clock_cpu+0xe/0x1a0
  ? drain_workqueue+0x41/0x140
  drain_workqueue+0x80/0x140
  destroy_workqueue+0x47/0x4f0
  ? blk_mq_freeze_queue_wait+0xac/0xd0
  __loop_clr_fd+0xb4/0x400 [loop]
  ? __mutex_unlock_slowpath+0x35/0x230
  blkdev_put+0x14a/0x1d0
  blkdev_close+0x1c/0x20
  __fput+0xfd/0x220
  task_work_run+0x69/0xc0
  exit_to_user_mode_prepare+0x1ce/0x1f0
  syscall_exit_to_user_mode+0x26/0x60
  do_syscall_64+0x4c/0xb0
  entry_SYSCALL_64_after_hwframe+0x44/0xae
 RIP: 0033:0x7f0fd4c661f7
 Code: 00 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 41 c3 48 83 ec 18 89 7c 24 0c e8 13 fc ff ff
 RSP: 002b:00007ffd1c9e9fd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
 RAX: 0000000000000000 RBX: 00007f0fd46be6c8 RCX: 00007f0fd4c661f7
 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006
 RBP: 0000000000000006 R08: 000055fff1eaf400 R09: 0000000000000000
 R10: 00007f0fd46be6c8 R11: 0000000000000246 R12: 0000000000000000
 R13: 0000000000000000 R14: 0000000000002f08 R15: 00007ffd1c9ea050

Commit 1c500ad ("loop: reduce the loop_ctl_mutex scope") is for
breaking "loop_ctl_mutex => &lo->lo_mutex" dependency chain. But enabling
a different block module results in forming circular locking dependency
due to shared major_names_lock mutex.

The simplest fix is to call probe function without holding
major_names_lock [1], but Christoph Hellwig does not like such idea.
Therefore, instead of holding major_names_lock in blkdev_show(),
introduce a different lock for blkdev_show() in order to break
"sb_writers#$N => &p->lock => major_names_lock" dependency chain.

Link: https://lkml.kernel.org/r/b2af8a5b-3c1b-204e-7f56-bea0b15848d6@i-love.sakura.ne.jp [1]
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Link: https://lore.kernel.org/r/18a02da2-0bf3-550e-b071-2b4ab13c49f0@i-love.sakura.ne.jp
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
esmil pushed a commit that referenced this pull request Sep 26, 2021
On SiFive Unmatched, I recently fell onto the following BUG when booting:

[    0.000000] ftrace: allocating 36610 entries in 144 pages
[    0.000000] Oops - illegal instruction [#1]
[    0.000000] Modules linked in:
[    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.13.1+ #5
[    0.000000] Hardware name: SiFive HiFive Unmatched A00 (DT)
[    0.000000] epc : riscv_cpuid_to_hartid_mask+0x6/0xae
[    0.000000]  ra : __sbi_rfence_v02+0xc8/0x10a
[    0.000000] epc : ffffffff80007240 ra : ffffffff80009964 sp : ffffffff81803e10
[    0.000000]  gp : ffffffff81a1ea70 tp : ffffffff8180f500 t0 : ffffffe07fe30000
[    0.000000]  t1 : 0000000000000004 t2 : 0000000000000000 s0 : ffffffff81803e60
[    0.000000]  s1 : 0000000000000000 a0 : ffffffff81a22238 a1 : ffffffff81803e10
[    0.000000]  a2 : 0000000000000000 a3 : 0000000000000000 a4 : 0000000000000000
[    0.000000]  a5 : 0000000000000000 a6 : ffffffff8000989c a7 : 0000000052464e43
[    0.000000]  s2 : ffffffff81a220c8 s3 : 0000000000000000 s4 : 0000000000000000
[    0.000000]  s5 : 0000000000000000 s6 : 0000000200000100 s7 : 0000000000000001
[    0.000000]  s8 : ffffffe07fe04040 s9 : ffffffff81a22c80 s10: 0000000000001000
[    0.000000]  s11: 0000000000000004 t3 : 0000000000000001 t4 : 0000000000000008
[    0.000000]  t5 : ffffffcf04000808 t6 : ffffffe3ffddf188
[    0.000000] status: 0000000200000100 badaddr: 0000000000000000 cause: 0000000000000002
[    0.000000] [<ffffffff80007240>] riscv_cpuid_to_hartid_mask+0x6/0xae
[    0.000000] [<ffffffff80009474>] sbi_remote_fence_i+0x1e/0x26
[    0.000000] [<ffffffff8000b8f4>] flush_icache_all+0x12/0x1a
[    0.000000] [<ffffffff8000666c>] patch_text_nosync+0x26/0x32
[    0.000000] [<ffffffff8000884e>] ftrace_init_nop+0x52/0x8c
[    0.000000] [<ffffffff800f051e>] ftrace_process_locs.isra.0+0x29c/0x360
[    0.000000] [<ffffffff80a0e3c6>] ftrace_init+0x80/0x130
[    0.000000] [<ffffffff80a00f8c>] start_kernel+0x5c4/0x8f6
[    0.000000] ---[ end trace f67eb9af4d8d492b ]---
[    0.000000] Kernel panic - not syncing: Attempted to kill the idle task!
[    0.000000] ---[ end Kernel panic - not syncing: Attempted to kill the idle task! ]---

While ftrace is looping over a list of addresses to patch, it always failed
when patching the same function: riscv_cpuid_to_hartid_mask. Looking at the
backtrace, the illegal instruction is encountered in this same function.
However, patch_text_nosync, after patching the instructions, calls
flush_icache_range. But looking at what happens in this function:

flush_icache_range -> flush_icache_all
                   -> sbi_remote_fence_i
                   -> __sbi_rfence_v02
                   -> riscv_cpuid_to_hartid_mask

The icache and dcache of the current cpu are never synchronized between the
patching of riscv_cpuid_to_hartid_mask and calling this same function.

So fix this by flushing the current cpu's icache before asking for the other
cpus to do the same.

Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
esmil pushed a commit that referenced this pull request Sep 27, 2021
Peter's e-mail in MAINTAINERS is defunct:
This is the qmail-send program at a.mx.sunsite.dk.
<jacmet@sunsite.dk>:
      Sorry, no mailbox here by that name. (#5.1.1)

Peter says:
** Ahh yes, it should be changed to peter@korsgaard.com.

However he also says:
** I haven't had access to c67x00 hw for quite some years though, so maybe
** it should be marked Orphan instead?

So change as he wishes.

Cc: Peter Korsgaard <peter@korsgaard.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-usb@vger.kernel.org
Acked-by: Peter Korsgaard <peter@korsgaard.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210922063008.25758-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
esmil pushed a commit that referenced this pull request Sep 27, 2021
On SiFive Unmatched, I recently fell onto the following BUG when booting:

[    0.000000] ftrace: allocating 36610 entries in 144 pages
[    0.000000] Oops - illegal instruction [#1]
[    0.000000] Modules linked in:
[    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.13.1+ #5
[    0.000000] Hardware name: SiFive HiFive Unmatched A00 (DT)
[    0.000000] epc : riscv_cpuid_to_hartid_mask+0x6/0xae
[    0.000000]  ra : __sbi_rfence_v02+0xc8/0x10a
[    0.000000] epc : ffffffff80007240 ra : ffffffff80009964 sp : ffffffff81803e10
[    0.000000]  gp : ffffffff81a1ea70 tp : ffffffff8180f500 t0 : ffffffe07fe30000
[    0.000000]  t1 : 0000000000000004 t2 : 0000000000000000 s0 : ffffffff81803e60
[    0.000000]  s1 : 0000000000000000 a0 : ffffffff81a22238 a1 : ffffffff81803e10
[    0.000000]  a2 : 0000000000000000 a3 : 0000000000000000 a4 : 0000000000000000
[    0.000000]  a5 : 0000000000000000 a6 : ffffffff8000989c a7 : 0000000052464e43
[    0.000000]  s2 : ffffffff81a220c8 s3 : 0000000000000000 s4 : 0000000000000000
[    0.000000]  s5 : 0000000000000000 s6 : 0000000200000100 s7 : 0000000000000001
[    0.000000]  s8 : ffffffe07fe04040 s9 : ffffffff81a22c80 s10: 0000000000001000
[    0.000000]  s11: 0000000000000004 t3 : 0000000000000001 t4 : 0000000000000008
[    0.000000]  t5 : ffffffcf04000808 t6 : ffffffe3ffddf188
[    0.000000] status: 0000000200000100 badaddr: 0000000000000000 cause: 0000000000000002
[    0.000000] [<ffffffff80007240>] riscv_cpuid_to_hartid_mask+0x6/0xae
[    0.000000] [<ffffffff80009474>] sbi_remote_fence_i+0x1e/0x26
[    0.000000] [<ffffffff8000b8f4>] flush_icache_all+0x12/0x1a
[    0.000000] [<ffffffff8000666c>] patch_text_nosync+0x26/0x32
[    0.000000] [<ffffffff8000884e>] ftrace_init_nop+0x52/0x8c
[    0.000000] [<ffffffff800f051e>] ftrace_process_locs.isra.0+0x29c/0x360
[    0.000000] [<ffffffff80a0e3c6>] ftrace_init+0x80/0x130
[    0.000000] [<ffffffff80a00f8c>] start_kernel+0x5c4/0x8f6
[    0.000000] ---[ end trace f67eb9af4d8d492b ]---
[    0.000000] Kernel panic - not syncing: Attempted to kill the idle task!
[    0.000000] ---[ end Kernel panic - not syncing: Attempted to kill the idle task! ]---

While ftrace is looping over a list of addresses to patch, it always failed
when patching the same function: riscv_cpuid_to_hartid_mask. Looking at the
backtrace, the illegal instruction is encountered in this same function.
However, patch_text_nosync, after patching the instructions, calls
flush_icache_range. But looking at what happens in this function:

flush_icache_range -> flush_icache_all
                   -> sbi_remote_fence_i
                   -> __sbi_rfence_v02
                   -> riscv_cpuid_to_hartid_mask

The icache and dcache of the current cpu are never synchronized between the
patching of riscv_cpuid_to_hartid_mask and calling this same function.

So fix this by flushing the current cpu's icache before asking for the other
cpus to do the same.

Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
esmil pushed a commit that referenced this pull request Oct 3, 2021
On SiFive Unmatched, I recently fell onto the following BUG when booting:

[    0.000000] ftrace: allocating 36610 entries in 144 pages
[    0.000000] Oops - illegal instruction [#1]
[    0.000000] Modules linked in:
[    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.13.1+ #5
[    0.000000] Hardware name: SiFive HiFive Unmatched A00 (DT)
[    0.000000] epc : riscv_cpuid_to_hartid_mask+0x6/0xae
[    0.000000]  ra : __sbi_rfence_v02+0xc8/0x10a
[    0.000000] epc : ffffffff80007240 ra : ffffffff80009964 sp : ffffffff81803e10
[    0.000000]  gp : ffffffff81a1ea70 tp : ffffffff8180f500 t0 : ffffffe07fe30000
[    0.000000]  t1 : 0000000000000004 t2 : 0000000000000000 s0 : ffffffff81803e60
[    0.000000]  s1 : 0000000000000000 a0 : ffffffff81a22238 a1 : ffffffff81803e10
[    0.000000]  a2 : 0000000000000000 a3 : 0000000000000000 a4 : 0000000000000000
[    0.000000]  a5 : 0000000000000000 a6 : ffffffff8000989c a7 : 0000000052464e43
[    0.000000]  s2 : ffffffff81a220c8 s3 : 0000000000000000 s4 : 0000000000000000
[    0.000000]  s5 : 0000000000000000 s6 : 0000000200000100 s7 : 0000000000000001
[    0.000000]  s8 : ffffffe07fe04040 s9 : ffffffff81a22c80 s10: 0000000000001000
[    0.000000]  s11: 0000000000000004 t3 : 0000000000000001 t4 : 0000000000000008
[    0.000000]  t5 : ffffffcf04000808 t6 : ffffffe3ffddf188
[    0.000000] status: 0000000200000100 badaddr: 0000000000000000 cause: 0000000000000002
[    0.000000] [<ffffffff80007240>] riscv_cpuid_to_hartid_mask+0x6/0xae
[    0.000000] [<ffffffff80009474>] sbi_remote_fence_i+0x1e/0x26
[    0.000000] [<ffffffff8000b8f4>] flush_icache_all+0x12/0x1a
[    0.000000] [<ffffffff8000666c>] patch_text_nosync+0x26/0x32
[    0.000000] [<ffffffff8000884e>] ftrace_init_nop+0x52/0x8c
[    0.000000] [<ffffffff800f051e>] ftrace_process_locs.isra.0+0x29c/0x360
[    0.000000] [<ffffffff80a0e3c6>] ftrace_init+0x80/0x130
[    0.000000] [<ffffffff80a00f8c>] start_kernel+0x5c4/0x8f6
[    0.000000] ---[ end trace f67eb9af4d8d492b ]---
[    0.000000] Kernel panic - not syncing: Attempted to kill the idle task!
[    0.000000] ---[ end Kernel panic - not syncing: Attempted to kill the idle task! ]---

While ftrace is looping over a list of addresses to patch, it always failed
when patching the same function: riscv_cpuid_to_hartid_mask. Looking at the
backtrace, the illegal instruction is encountered in this same function.
However, patch_text_nosync, after patching the instructions, calls
flush_icache_range. But looking at what happens in this function:

flush_icache_range -> flush_icache_all
                   -> sbi_remote_fence_i
                   -> __sbi_rfence_v02
                   -> riscv_cpuid_to_hartid_mask

The icache and dcache of the current cpu are never synchronized between the
patching of riscv_cpuid_to_hartid_mask and calling this same function.

So fix this by flushing the current cpu's icache before asking for the other
cpus to do the same.

Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
esmil pushed a commit that referenced this pull request Oct 11, 2021
On SiFive Unmatched, I recently fell onto the following BUG when booting:

[    0.000000] ftrace: allocating 36610 entries in 144 pages
[    0.000000] Oops - illegal instruction [#1]
[    0.000000] Modules linked in:
[    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.13.1+ #5
[    0.000000] Hardware name: SiFive HiFive Unmatched A00 (DT)
[    0.000000] epc : riscv_cpuid_to_hartid_mask+0x6/0xae
[    0.000000]  ra : __sbi_rfence_v02+0xc8/0x10a
[    0.000000] epc : ffffffff80007240 ra : ffffffff80009964 sp : ffffffff81803e10
[    0.000000]  gp : ffffffff81a1ea70 tp : ffffffff8180f500 t0 : ffffffe07fe30000
[    0.000000]  t1 : 0000000000000004 t2 : 0000000000000000 s0 : ffffffff81803e60
[    0.000000]  s1 : 0000000000000000 a0 : ffffffff81a22238 a1 : ffffffff81803e10
[    0.000000]  a2 : 0000000000000000 a3 : 0000000000000000 a4 : 0000000000000000
[    0.000000]  a5 : 0000000000000000 a6 : ffffffff8000989c a7 : 0000000052464e43
[    0.000000]  s2 : ffffffff81a220c8 s3 : 0000000000000000 s4 : 0000000000000000
[    0.000000]  s5 : 0000000000000000 s6 : 0000000200000100 s7 : 0000000000000001
[    0.000000]  s8 : ffffffe07fe04040 s9 : ffffffff81a22c80 s10: 0000000000001000
[    0.000000]  s11: 0000000000000004 t3 : 0000000000000001 t4 : 0000000000000008
[    0.000000]  t5 : ffffffcf04000808 t6 : ffffffe3ffddf188
[    0.000000] status: 0000000200000100 badaddr: 0000000000000000 cause: 0000000000000002
[    0.000000] [<ffffffff80007240>] riscv_cpuid_to_hartid_mask+0x6/0xae
[    0.000000] [<ffffffff80009474>] sbi_remote_fence_i+0x1e/0x26
[    0.000000] [<ffffffff8000b8f4>] flush_icache_all+0x12/0x1a
[    0.000000] [<ffffffff8000666c>] patch_text_nosync+0x26/0x32
[    0.000000] [<ffffffff8000884e>] ftrace_init_nop+0x52/0x8c
[    0.000000] [<ffffffff800f051e>] ftrace_process_locs.isra.0+0x29c/0x360
[    0.000000] [<ffffffff80a0e3c6>] ftrace_init+0x80/0x130
[    0.000000] [<ffffffff80a00f8c>] start_kernel+0x5c4/0x8f6
[    0.000000] ---[ end trace f67eb9af4d8d492b ]---
[    0.000000] Kernel panic - not syncing: Attempted to kill the idle task!
[    0.000000] ---[ end Kernel panic - not syncing: Attempted to kill the idle task! ]---

While ftrace is looping over a list of addresses to patch, it always failed
when patching the same function: riscv_cpuid_to_hartid_mask. Looking at the
backtrace, the illegal instruction is encountered in this same function.
However, patch_text_nosync, after patching the instructions, calls
flush_icache_range. But looking at what happens in this function:

flush_icache_range -> flush_icache_all
                   -> sbi_remote_fence_i
                   -> __sbi_rfence_v02
                   -> riscv_cpuid_to_hartid_mask

The icache and dcache of the current cpu are never synchronized between the
patching of riscv_cpuid_to_hartid_mask and calling this same function.

So fix this by flushing the current cpu's icache before asking for the other
cpus to do the same.

Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
Fixes: fab957c ("RISC-V: Atomic and Locking Code")
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
esmil pushed a commit that referenced this pull request Oct 31, 2021
The Xen interrupt injection for event channels relies on accessing the
guest's vcpu_info structure in __kvm_xen_has_interrupt(), through a
gfn_to_hva_cache.

This requires the srcu lock to be held, which is mostly the case except
for this code path:

[   11.822877] WARNING: suspicious RCU usage
[   11.822965] -----------------------------
[   11.823013] include/linux/kvm_host.h:664 suspicious rcu_dereference_check() usage!
[   11.823131]
[   11.823131] other info that might help us debug this:
[   11.823131]
[   11.823196]
[   11.823196] rcu_scheduler_active = 2, debug_locks = 1
[   11.823253] 1 lock held by dom:0/90:
[   11.823292]  #0: ffff998956ec8118 (&vcpu->mutex){+.+.}, at: kvm_vcpu_ioctl+0x85/0x680
[   11.823379]
[   11.823379] stack backtrace:
[   11.823428] CPU: 2 PID: 90 Comm: dom:0 Kdump: loaded Not tainted 5.4.34+ #5
[   11.823496] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014
[   11.823612] Call Trace:
[   11.823645]  dump_stack+0x7a/0xa5
[   11.823681]  lockdep_rcu_suspicious+0xc5/0x100
[   11.823726]  __kvm_xen_has_interrupt+0x179/0x190
[   11.823773]  kvm_cpu_has_extint+0x6d/0x90
[   11.823813]  kvm_cpu_accept_dm_intr+0xd/0x40
[   11.823853]  kvm_vcpu_ready_for_interrupt_injection+0x20/0x30
              < post_kvm_run_save() inlined here >
[   11.823906]  kvm_arch_vcpu_ioctl_run+0x135/0x6a0
[   11.823947]  kvm_vcpu_ioctl+0x263/0x680

Fixes: 40da8cc ("KVM: x86/xen: Add event channel interrupt vector upcall")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Cc: stable@vger.kernel.org
Message-Id: <606aaaf29fca3850a63aa4499826104e77a72346.camel@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
esmil pushed a commit that referenced this pull request Nov 10, 2021
As a full union is always sent, ensure all bytes of the union are
initialized with memset to avoid msan warnings of use of uninitialized
memory.

An example warning from the daemon test:

Uninitialized bytes in __interceptor_write at offset 71 inside [0x7ffd98da6280, 72)
==11602==WARNING: MemorySanitizer: use-of-uninitialized-value
    #0 0x5597edccdbe4 in ion tools/lib/perf/lib.c:18:6
    #1 0x5597edccdbe4 in writen tools/lib/perf/lib.c:47:9
    #2 0x5597ed221d30 in send_cmd tools/perf/builtin-daemon.c:1376:22
    #3 0x5597ed21b48c in cmd_daemon tools/perf/builtin-daemon.c
    #4 0x5597ed1d6b67 in run_builtin tools/perf/perf.c:313:11
    #5 0x5597ed1d6036 in handle_internal_command tools/perf/perf.c:365:8
    #6 0x5597ed1d6036 in run_argv tools/perf/perf.c:409:2
    #7 0x5597ed1d6036 in main tools/perf/perf.c:539:3

SUMMARY: MemorySanitizer: use-of-uninitialized-value tools/lib/perf/lib.c:18:6 in ion
Exiting

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20210617055554.1917997-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
esmil pushed a commit that referenced this pull request Nov 10, 2021
Host crashes when pci_enable_atomic_ops_to_root() is called for VFs with
virtual buses. The virtual buses added to SR-IOV have bus->self set to NULL
and host crashes due to this.

  PID: 4481   TASK: ffff89c6941b0000  CPU: 53  COMMAND: "bash"
  ...
   #3 [ffff9a9481713808] oops_end at ffffffffb9025cd6
   #4 [ffff9a9481713828] page_fault_oops at ffffffffb906e417
   #5 [ffff9a9481713888] exc_page_fault at ffffffffb9a0ad14
   #6 [ffff9a94817138b0] asm_exc_page_fault at ffffffffb9c00ace
      [exception RIP: pcie_capability_read_dword+28]
      RIP: ffffffffb952fd5c  RSP: ffff9a9481713960  RFLAGS: 00010246
      RAX: 0000000000000001  RBX: ffff89c6b1096000  RCX: 0000000000000000
      RDX: ffff9a9481713990  RSI: 0000000000000024  RDI: 0000000000000000
      RBP: 0000000000000080   R8: 0000000000000008   R9: ffff89c64341a2f8
      R10: 0000000000000002  R11: 0000000000000000  R12: ffff89c648bab000
      R13: 0000000000000000  R14: 0000000000000000  R15: ffff89c648bab0c8
      ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
   #7 [ffff9a9481713988] pci_enable_atomic_ops_to_root at ffffffffb95359a6
   #8 [ffff9a94817139c0] bnxt_qplib_determine_atomics at ffffffffc08c1a33 [bnxt_re]
   #9 [ffff9a94817139d0] bnxt_re_dev_init at ffffffffc08ba2d1 [bnxt_re]

Per PCIe r5.0, sec 9.3.5.10, the AtomicOp Requester Enable bit in Device
Control 2 is reserved for VFs.  The PF value applies to all associated VFs.

Return -EINVAL if pci_enable_atomic_ops_to_root() is called for a VF.

Link: https://lore.kernel.org/r/1631354585-16597-1-git-send-email-selvin.xavier@broadcom.com
Fixes: 35f5ace ("RDMA/bnxt_re: Enable global atomic ops if platform supports")
Fixes: 430a236 ("PCI: Add pci_enable_atomic_ops_to_root()")
Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Andy Gospodarek <gospo@broadcom.com>
esmil pushed a commit that referenced this pull request Nov 10, 2021
Patch series "Solve silent data loss caused by poisoned page cache (shmem/tmpfs)", v5.

When discussing the patch that splits page cache THP in order to offline
the poisoned page, Noaya mentioned there is a bigger problem [1] that
prevents this from working since the page cache page will be truncated
if uncorrectable errors happen.  By looking this deeper it turns out
this approach (truncating poisoned page) may incur silent data loss for
all non-readonly filesystems if the page is dirty.  It may be worse for
in-memory filesystem, e.g.  shmem/tmpfs since the data blocks are
actually gone.

To solve this problem we could keep the poisoned dirty page in page
cache then notify the users on any later access, e.g.  page fault,
read/write, etc.  The clean page could be truncated as is since they can
be reread from disk later on.

The consequence is the filesystems may find poisoned page and manipulate
it as healthy page since all the filesystems actually don't check if the
page is poisoned or not in all the relevant paths except page fault.  In
general, we need make the filesystems be aware of poisoned page before
we could keep the poisoned page in page cache in order to solve the data
loss problem.

To make filesystems be aware of poisoned page we should consider:

 - The page should be not written back: clearing dirty flag could
   prevent from writeback.

 - The page should not be dropped (it shows as a clean page) by drop
   caches or other callers: the refcount pin from hwpoison could prevent
   from invalidating (called by cache drop, inode cache shrinking, etc),
   but it doesn't avoid invalidation in DIO path.

 - The page should be able to get truncated/hole punched/unlinked: it
   works as it is.

 - Notify users when the page is accessed, e.g. read/write, page fault
   and other paths (compression, encryption, etc).

The scope of the last one is huge since almost all filesystems need do
it once a page is returned from page cache lookup.  There are a couple
of options to do it:

 1. Check hwpoison flag for every path, the most straightforward way.

 2. Return NULL for poisoned page from page cache lookup, the most
    callsites check if NULL is returned, this should have least work I
    think. But the error handling in filesystems just return -ENOMEM,
    the error code will incur confusion to the users obviously.

 3. To improve #2, we could return error pointer, e.g. ERR_PTR(-EIO),
    but this will involve significant amount of code change as well
    since all the paths need check if the pointer is ERR or not just
    like option #1.

I did prototypes for both #1 and #3, but it seems #3 may require more
changes than #1.  For #3 ERR_PTR will be returned so all the callers
need to check the return value otherwise invalid pointer may be
dereferenced, but not all callers really care about the content of the
page, for example, partial truncate which just sets the truncated range
in one page to 0.  So for such paths it needs additional modification if
ERR_PTR is returned.  And if the callers have their own way to handle
the problematic pages we need to add a new FGP flag to tell FGP
functions to return the pointer to the page.

It may happen very rarely, but once it happens the consequence (data
corruption) could be very bad and it is very hard to debug.  It seems
this problem had been slightly discussed before, but seems no action was
taken at that time.  [2]

As the aforementioned investigation, it needs huge amount of work to
solve the potential data loss for all filesystems.  But it is much
easier for in-memory filesystems and such filesystems actually suffer
more than others since even the data blocks are gone due to truncating.
So this patchset starts from shmem/tmpfs by taking option #1.

TODO:
* The unpoison has been broken since commit 0ed950d ("mm,hwpoison: make
  get_hwpoison_page() call get_any_page()"), and this patch series make
  refcount check for unpoisoning shmem page fail.
* Expand to other filesystems.  But I haven't heard feedback from filesystem
  developers yet.

Patch breakdown:
Patch #1: cleanup, depended by patch #2
Patch #2: fix THP with hwpoisoned subpage(s) PMD map bug
Patch #3: coding style cleanup
Patch #4: refactor and preparation.
Patch #5: keep the poisoned page in page cache and handle such case for all
          the paths.
Patch #6: the previous patches unblock page cache THP split, so this patch
          add page cache THP split support.

This patch (of 4):

A minor cleanup to the indent.

Link: https://lkml.kernel.org/r/20211020210755.23964-1-shy828301@gmail.com
Link: https://lkml.kernel.org/r/20211020210755.23964-4-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
esmil pushed a commit that referenced this pull request Nov 10, 2021
After removing /dev/kmem, sanitizing /proc/kcore and handling /dev/mem,
this series tackles the last sane way how a VM could accidentially
access logically unplugged memory managed by a virtio-mem device:
/proc/vmcore

When dumping memory via "makedumpfile", PG_offline pages, used by
virtio-mem to flag logically unplugged memory, are already properly
excluded; however, especially when accessing/copying /proc/vmcore "the
usual way", we can still end up reading logically unplugged memory part
of a virtio-mem device.

Patch #1-#3 are cleanups.  Patch #4 extends the existing
oldmem_pfn_is_ram mechanism.  Patch #5-#7 are virtio-mem refactorings
for patch #8, which implements the virtio-mem logic to query the state
of device blocks.

Patch #8:
 "Although virtio-mem currently supports reading unplugged memory in the
  hypervisor, this will change in the future, indicated to the device
  via a new feature flag. We similarly sanitized /proc/kcore access
  recently.
  [...]
  Distributions that support virtio-mem+kdump have to make sure that the
  virtio_mem module will be part of the kdump kernel or the kdump
  initrd; dracut was recently [2] extended to include virtio-mem in the
  generated initrd. As long as no special kdump kernels are used, this
  will automatically make sure that virtio-mem will be around in the
  kdump initrd and sanitize /proc/vmcore access -- with dracut"

This is the last remaining bit to support
VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE [3] in the Linux implementation of
virtio-mem.

Note: this is best-effort.  We'll never be able to control what runs
inside the second kernel, really, but we also don't have to care: we
only care about sane setups where we don't want our VM getting zapped
once we touch the wrong memory location while dumping.  While we usually
expect sane setups to use "makedumfile", nothing really speaks against
just copying /proc/vmcore, especially in environments where HWpoisioning
isn't typically expected.  Also, we really don't want to put all our
trust completely on the memmap, so sanitizing also makes sense when just
using "makedumpfile".

[1] https://lkml.kernel.org/r/20210526093041.8800-1-david@redhat.com
[2] dracutdevs/dracut#1157
[3] https://lists.oasis-open.org/archives/virtio-comment/202109/msg00021.html

This patch (of 9):

The callback is only used for the vmcore nowadays.

Link: https://lkml.kernel.org/r/20211005121430.30136-1-david@redhat.com
Link: https://lkml.kernel.org/r/20211005121430.30136-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Boris Ostrovsky <boris.ostrvsky@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
esmil pushed a commit that referenced this pull request Nov 10, 2021
Patch series "kcov: PREEMPT_RT fixup + misc", v2.

The last patch in series is follow-up to address the PREEMPT_RT issue
within in kcov reported by Clark [1].  Patches 1-3 are smaller things that
I noticed while staring at it.  Patch 4 is small change which makes
replacement in #5 simpler / more obvious.

[1] https://lkml.kernel.org/r/20210809155909.333073de@theseus.lan

This patch (of 5):

The first example code has includes at the top, the following two
example share that part. The last example (remote coverage collection)
requires the linux/types.h header file due its __aligned_u64 usage.

Add the linux/types.h to the top most example and a comment that the
header files from above are required as it is done in the second
example.

Link: https://lkml.kernel.org/r/20210923164741.1859522-1-bigeasy@linutronix.de
Link: https://lore.kernel.org/r/20210830172627.267989-2-bigeasy@linutronix.de
Link: https://lkml.kernel.org/r/20210923164741.1859522-2-bigeasy@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Marco Elver <elver@google.com>
Tested-by: Marco Elver <elver@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Clark Williams <williams@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
esmil pushed a commit that referenced this pull request Nov 13, 2021
It is generally unsafe to call put_device() with dpm_list_mtx held,
because the given device's release routine may carry out an action
depending on that lock which then may deadlock, so modify the
system-wide suspend and resume of devices to always drop dpm_list_mtx
before calling put_device() (and adjust white space somewhat while
at it).

For instance, this prevents the following splat from showing up in
the kernel log after a system resume in certain configurations:

[ 3290.969514] ======================================================
[ 3290.969517] WARNING: possible circular locking dependency detected
[ 3290.969519] 5.15.0+ #2420 Tainted: G S
[ 3290.969523] ------------------------------------------------------
[ 3290.969525] systemd-sleep/4553 is trying to acquire lock:
[ 3290.969529] ffff888117ab1138 ((wq_completion)hci0#2){+.+.}-{0:0}, at: flush_workqueue+0x87/0x4a0
[ 3290.969554]
               but task is already holding lock:
[ 3290.969556] ffffffff8280fca8 (dpm_list_mtx){+.+.}-{3:3}, at: dpm_resume+0x12e/0x3e0
[ 3290.969571]
               which lock already depends on the new lock.

[ 3290.969573]
               the existing dependency chain (in reverse order) is:
[ 3290.969575]
               -> #3 (dpm_list_mtx){+.+.}-{3:3}:
[ 3290.969583]        __mutex_lock+0x9d/0xa30
[ 3290.969591]        device_pm_add+0x2e/0xe0
[ 3290.969597]        device_add+0x4d5/0x8f0
[ 3290.969605]        hci_conn_add_sysfs+0x43/0xb0 [bluetooth]
[ 3290.969689]        hci_conn_complete_evt.isra.71+0x124/0x750 [bluetooth]
[ 3290.969747]        hci_event_packet+0xd6c/0x28a0 [bluetooth]
[ 3290.969798]        hci_rx_work+0x213/0x640 [bluetooth]
[ 3290.969842]        process_one_work+0x2aa/0x650
[ 3290.969851]        worker_thread+0x39/0x400
[ 3290.969859]        kthread+0x142/0x170
[ 3290.969865]        ret_from_fork+0x22/0x30
[ 3290.969872]
               -> #2 (&hdev->lock){+.+.}-{3:3}:
[ 3290.969881]        __mutex_lock+0x9d/0xa30
[ 3290.969887]        hci_event_packet+0xba/0x28a0 [bluetooth]
[ 3290.969935]        hci_rx_work+0x213/0x640 [bluetooth]
[ 3290.969978]        process_one_work+0x2aa/0x650
[ 3290.969985]        worker_thread+0x39/0x400
[ 3290.969993]        kthread+0x142/0x170
[ 3290.969999]        ret_from_fork+0x22/0x30
[ 3290.970004]
               -> #1 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}:
[ 3290.970013]        process_one_work+0x27d/0x650
[ 3290.970020]        worker_thread+0x39/0x400
[ 3290.970028]        kthread+0x142/0x170
[ 3290.970033]        ret_from_fork+0x22/0x30
[ 3290.970038]
               -> #0 ((wq_completion)hci0#2){+.+.}-{0:0}:
[ 3290.970047]        __lock_acquire+0x15cb/0x1b50
[ 3290.970054]        lock_acquire+0x26c/0x300
[ 3290.970059]        flush_workqueue+0xae/0x4a0
[ 3290.970066]        drain_workqueue+0xa1/0x130
[ 3290.970073]        destroy_workqueue+0x34/0x1f0
[ 3290.970081]        hci_release_dev+0x49/0x180 [bluetooth]
[ 3290.970130]        bt_host_release+0x1d/0x30 [bluetooth]
[ 3290.970195]        device_release+0x33/0x90
[ 3290.970201]        kobject_release+0x63/0x160
[ 3290.970211]        dpm_resume+0x164/0x3e0
[ 3290.970215]        dpm_resume_end+0xd/0x20
[ 3290.970220]        suspend_devices_and_enter+0x1a4/0xba0
[ 3290.970229]        pm_suspend+0x26b/0x310
[ 3290.970236]        state_store+0x42/0x90
[ 3290.970243]        kernfs_fop_write_iter+0x135/0x1b0
[ 3290.970251]        new_sync_write+0x125/0x1c0
[ 3290.970257]        vfs_write+0x360/0x3c0
[ 3290.970263]        ksys_write+0xa7/0xe0
[ 3290.970269]        do_syscall_64+0x3a/0x80
[ 3290.970276]        entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 3290.970284]
               other info that might help us debug this:

[ 3290.970285] Chain exists of:
                 (wq_completion)hci0#2 --> &hdev->lock --> dpm_list_mtx

[ 3290.970297]  Possible unsafe locking scenario:

[ 3290.970299]        CPU0                    CPU1
[ 3290.970300]        ----                    ----
[ 3290.970302]   lock(dpm_list_mtx);
[ 3290.970306]                                lock(&hdev->lock);
[ 3290.970310]                                lock(dpm_list_mtx);
[ 3290.970314]   lock((wq_completion)hci0#2);
[ 3290.970319]
                *** DEADLOCK ***

[ 3290.970321] 7 locks held by systemd-sleep/4553:
[ 3290.970325]  #0: ffff888103bcd448 (sb_writers#4){.+.+}-{0:0}, at: ksys_write+0xa7/0xe0
[ 3290.970341]  #1: ffff888115a14488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x103/0x1b0
[ 3290.970355]  #2: ffff888100f719e0 (kn->active#233){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x10c/0x1b0
[ 3290.970369]  #3: ffffffff82661048 (autosleep_lock){+.+.}-{3:3}, at: state_store+0x12/0x90
[ 3290.970384]  #4: ffffffff82658ac8 (system_transition_mutex){+.+.}-{3:3}, at: pm_suspend+0x9f/0x310
[ 3290.970399]  #5: ffffffff827f2a48 (acpi_scan_lock){+.+.}-{3:3}, at: acpi_suspend_begin+0x4c/0x80
[ 3290.970416]  #6: ffffffff8280fca8 (dpm_list_mtx){+.+.}-{3:3}, at: dpm_resume+0x12e/0x3e0
[ 3290.970428]
               stack backtrace:
[ 3290.970431] CPU: 3 PID: 4553 Comm: systemd-sleep Tainted: G S                5.15.0+ #2420
[ 3290.970438] Hardware name: Dell Inc. XPS 13 9380/0RYJWW, BIOS 1.5.0 06/03/2019
[ 3290.970441] Call Trace:
[ 3290.970446]  dump_stack_lvl+0x44/0x57
[ 3290.970454]  check_noncircular+0x105/0x120
[ 3290.970468]  ? __lock_acquire+0x15cb/0x1b50
[ 3290.970474]  __lock_acquire+0x15cb/0x1b50
[ 3290.970487]  lock_acquire+0x26c/0x300
[ 3290.970493]  ? flush_workqueue+0x87/0x4a0
[ 3290.970503]  ? __raw_spin_lock_init+0x3b/0x60
[ 3290.970510]  ? lockdep_init_map_type+0x58/0x240
[ 3290.970519]  flush_workqueue+0xae/0x4a0
[ 3290.970526]  ? flush_workqueue+0x87/0x4a0
[ 3290.970544]  ? drain_workqueue+0xa1/0x130
[ 3290.970552]  drain_workqueue+0xa1/0x130
[ 3290.970561]  destroy_workqueue+0x34/0x1f0
[ 3290.970572]  hci_release_dev+0x49/0x180 [bluetooth]
[ 3290.970624]  bt_host_release+0x1d/0x30 [bluetooth]
[ 3290.970687]  device_release+0x33/0x90
[ 3290.970695]  kobject_release+0x63/0x160
[ 3290.970705]  dpm_resume+0x164/0x3e0
[ 3290.970710]  ? dpm_resume_early+0x251/0x3b0
[ 3290.970718]  dpm_resume_end+0xd/0x20
[ 3290.970723]  suspend_devices_and_enter+0x1a4/0xba0
[ 3290.970737]  pm_suspend+0x26b/0x310
[ 3290.970746]  state_store+0x42/0x90
[ 3290.970755]  kernfs_fop_write_iter+0x135/0x1b0
[ 3290.970764]  new_sync_write+0x125/0x1c0
[ 3290.970777]  vfs_write+0x360/0x3c0
[ 3290.970785]  ksys_write+0xa7/0xe0
[ 3290.970794]  do_syscall_64+0x3a/0x80
[ 3290.970803]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 3290.970811] RIP: 0033:0x7f41b1328164
[ 3290.970819] Code: 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 80 00 00 00 00 8b 05 4a d2 2c 00 48 63 ff 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 f3 c3 66 90 55 53 48 89 d5 48 89 f3 48 83
[ 3290.970824] RSP: 002b:00007ffe6ae21b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[ 3290.970831] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f41b1328164
[ 3290.970836] RDX: 0000000000000004 RSI: 000055965e651070 RDI: 0000000000000004
[ 3290.970839] RBP: 000055965e651070 R08: 000055965e64f390 R09: 00007f41b1e3d1c0
[ 3290.970843] R10: 000000000000000a R11: 0000000000000246 R12: 0000000000000004
[ 3290.970846] R13: 0000000000000001 R14: 000055965e64f2b0 R15: 0000000000000004

Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
esmil pushed a commit that referenced this pull request Nov 14, 2021
Convert the netfs helper library to use folios throughout, convert the 9p
and afs filesystems to use folios in their file I/O paths and convert the
ceph filesystem to use just enough folios to compile.

With these changes, afs passes -g quick xfstests.

Changes
=======
ver #5:
 - Got rid of folio_end{io,_read,_write}() and inlined the stuff it does
   instead (Willy decided he didn't want this after all).

ver #4:
 - Fixed a bug in afs_redirty_page() whereby it didn't set the next page
   index in the loop and returned too early.
 - Simplified a check in v9fs_vfs_write_folio_locked()[1].
 - Undid a change to afs_symlink_readpage()[1].
 - Used offset_in_folio() in afs_write_end()[1].
 - Changed from using page_endio() to folio_end{io,_read,_write}()[1].

ver #2:
 - Add 9p foliation.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Dominique Martinet <asmadeus@codewreck.org>
Tested-by: kafs-testing@auristor.com
cc: Matthew Wilcox (Oracle) <willy@infradead.org>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: v9fs-developer@lists.sourceforge.net
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/YYKa3bfQZxK5/wDN@casper.infradead.org/ [1]
Link: https://lore.kernel.org/r/2408234.1628687271@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/162877311459.3085614.10601478228012245108.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/162981153551.1901565.3124454657133703341.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/163005745264.2472992.9852048135392188995.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163584187452.4023316.500389675405550116.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/163649328026.309189.1124218109373941936.stgit@warthog.procyon.org.uk/ # v4
Link: https://lore.kernel.org/r/163657852454.834781.9265101983152100556.stgit@warthog.procyon.org.uk/ # v5
esmil pushed a commit that referenced this pull request Nov 14, 2021
The exit function fixes a memory leak with the src field as detected by
leak sanitizer. An example of which is:

Indirect leak of 25133184 byte(s) in 207 object(s) allocated from:
    #0 0x7f199ecfe987 in __interceptor_calloc libsanitizer/asan/asan_malloc_linux.cpp:154
    #1 0x55defe638224 in annotated_source__alloc_histograms util/annotate.c:803
    #2 0x55defe6397e4 in symbol__hists util/annotate.c:952
    #3 0x55defe639908 in symbol__inc_addr_samples util/annotate.c:968
    #4 0x55defe63aa29 in hist_entry__inc_addr_samples util/annotate.c:1119
    #5 0x55defe499a79 in hist_iter__report_callback tools/perf/builtin-report.c:182
    #6 0x55defe7a859d in hist_entry_iter__add util/hist.c:1236
    #7 0x55defe49aa63 in process_sample_event tools/perf/builtin-report.c:315
    #8 0x55defe731bc8 in evlist__deliver_sample util/session.c:1473
    #9 0x55defe731e38 in machines__deliver_event util/session.c:1510
    #10 0x55defe732a23 in perf_session__deliver_event util/session.c:1590
    #11 0x55defe72951e in ordered_events__deliver_event util/session.c:183
    #12 0x55defe740082 in do_flush util/ordered-events.c:244
    #13 0x55defe7407cb in __ordered_events__flush util/ordered-events.c:323
    #14 0x55defe740a61 in ordered_events__flush util/ordered-events.c:341
    #15 0x55defe73837f in __perf_session__process_events util/session.c:2390
    #16 0x55defe7385ff in perf_session__process_events util/session.c:2420
    ...

Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin Liška <mliska@suse.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20211112035124.94327-3-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
esmil pushed a commit that referenced this pull request Nov 21, 2021
[ Upstream commit 8ef9dc0 ]

We got the following lockdep splat while running fstests (specifically
btrfs/003 and btrfs/020 in a row) with the new rc.  This was uncovered
by 87579e9 ("loop: use worker per cgroup instead of kworker") which
converted loop to using workqueues, which comes with lockdep
annotations that don't exist with kworkers.  The lockdep splat is as
follows:

  WARNING: possible circular locking dependency detected
  5.14.0-rc2-custom+ #34 Not tainted
  ------------------------------------------------------
  losetup/156417 is trying to acquire lock:
  ffff9c7645b02d38 ((wq_completion)loop0){+.+.}-{0:0}, at: flush_workqueue+0x84/0x600

  but task is already holding lock:
  ffff9c7647395468 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x41/0x650 [loop]

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #5 (&lo->lo_mutex){+.+.}-{3:3}:
	 __mutex_lock+0xba/0x7c0
	 lo_open+0x28/0x60 [loop]
	 blkdev_get_whole+0x28/0xf0
	 blkdev_get_by_dev.part.0+0x168/0x3c0
	 blkdev_open+0xd2/0xe0
	 do_dentry_open+0x163/0x3a0
	 path_openat+0x74d/0xa40
	 do_filp_open+0x9c/0x140
	 do_sys_openat2+0xb1/0x170
	 __x64_sys_openat+0x54/0x90
	 do_syscall_64+0x3b/0x90
	 entry_SYSCALL_64_after_hwframe+0x44/0xae

  -> #4 (&disk->open_mutex){+.+.}-{3:3}:
	 __mutex_lock+0xba/0x7c0
	 blkdev_get_by_dev.part.0+0xd1/0x3c0
	 blkdev_get_by_path+0xc0/0xd0
	 btrfs_scan_one_device+0x52/0x1f0 [btrfs]
	 btrfs_control_ioctl+0xac/0x170 [btrfs]
	 __x64_sys_ioctl+0x83/0xb0
	 do_syscall_64+0x3b/0x90
	 entry_SYSCALL_64_after_hwframe+0x44/0xae

  -> #3 (uuid_mutex){+.+.}-{3:3}:
	 __mutex_lock+0xba/0x7c0
	 btrfs_rm_device+0x48/0x6a0 [btrfs]
	 btrfs_ioctl+0x2d1c/0x3110 [btrfs]
	 __x64_sys_ioctl+0x83/0xb0
	 do_syscall_64+0x3b/0x90
	 entry_SYSCALL_64_after_hwframe+0x44/0xae

  -> #2 (sb_writers#11){.+.+}-{0:0}:
	 lo_write_bvec+0x112/0x290 [loop]
	 loop_process_work+0x25f/0xcb0 [loop]
	 process_one_work+0x28f/0x5d0
	 worker_thread+0x55/0x3c0
	 kthread+0x140/0x170
	 ret_from_fork+0x22/0x30

  -> #1 ((work_completion)(&lo->rootcg_work)){+.+.}-{0:0}:
	 process_one_work+0x266/0x5d0
	 worker_thread+0x55/0x3c0
	 kthread+0x140/0x170
	 ret_from_fork+0x22/0x30

  -> #0 ((wq_completion)loop0){+.+.}-{0:0}:
	 __lock_acquire+0x1130/0x1dc0
	 lock_acquire+0xf5/0x320
	 flush_workqueue+0xae/0x600
	 drain_workqueue+0xa0/0x110
	 destroy_workqueue+0x36/0x250
	 __loop_clr_fd+0x9a/0x650 [loop]
	 lo_ioctl+0x29d/0x780 [loop]
	 block_ioctl+0x3f/0x50
	 __x64_sys_ioctl+0x83/0xb0
	 do_syscall_64+0x3b/0x90
	 entry_SYSCALL_64_after_hwframe+0x44/0xae

  other info that might help us debug this:
  Chain exists of:
    (wq_completion)loop0 --> &disk->open_mutex --> &lo->lo_mutex
   Possible unsafe locking scenario:
	 CPU0                    CPU1
	 ----                    ----
    lock(&lo->lo_mutex);
				 lock(&disk->open_mutex);
				 lock(&lo->lo_mutex);
    lock((wq_completion)loop0);

   *** DEADLOCK ***
  1 lock held by losetup/156417:
   #0: ffff9c7647395468 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x41/0x650 [loop]

  stack backtrace:
  CPU: 8 PID: 156417 Comm: losetup Not tainted 5.14.0-rc2-custom+ #34
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
  Call Trace:
   dump_stack_lvl+0x57/0x72
   check_noncircular+0x10a/0x120
   __lock_acquire+0x1130/0x1dc0
   lock_acquire+0xf5/0x320
   ? flush_workqueue+0x84/0x600
   flush_workqueue+0xae/0x600
   ? flush_workqueue+0x84/0x600
   drain_workqueue+0xa0/0x110
   destroy_workqueue+0x36/0x250
   __loop_clr_fd+0x9a/0x650 [loop]
   lo_ioctl+0x29d/0x780 [loop]
   ? __lock_acquire+0x3a0/0x1dc0
   ? update_dl_rq_load_avg+0x152/0x360
   ? lock_is_held_type+0xa5/0x120
   ? find_held_lock.constprop.0+0x2b/0x80
   block_ioctl+0x3f/0x50
   __x64_sys_ioctl+0x83/0xb0
   do_syscall_64+0x3b/0x90
   entry_SYSCALL_64_after_hwframe+0x44/0xae
  RIP: 0033:0x7f645884de6b

Usually the uuid_mutex exists to protect the fs_devices that map
together all of the devices that match a specific uuid.  In rm_device
we're messing with the uuid of a device, so it makes sense to protect
that here.

However in doing that it pulls in a whole host of lockdep dependencies,
as we call mnt_may_write() on the sb before we grab the uuid_mutex, thus
we end up with the dependency chain under the uuid_mutex being added
under the normal sb write dependency chain, which causes problems with
loop devices.

We don't need the uuid mutex here however.  If we call
btrfs_scan_one_device() before we scratch the super block we will find
the fs_devices and not find the device itself and return EBUSY because
the fs_devices is open.  If we call it after the scratch happens it will
not appear to be a valid btrfs file system.

We do not need to worry about other fs_devices modifying operations here
because we're protected by the exclusive operations locking.

So drop the uuid_mutex here in order to fix the lockdep splat.

A more detailed explanation from the discussion:

We are worried about rm and scan racing with each other, before this
change we'll zero the device out under the UUID mutex so when scan does
run it'll make sure that it can go through the whole device scan thing
without rm messing with us.

We aren't worried if the scratch happens first, because the result is we
don't think this is a btrfs device and we bail out.

The only case we are concerned with is we scratch _after_ scan is able
to read the superblock and gets a seemingly valid super block, so lets
consider this case.

Scan will call device_list_add() with the device we're removing.  We'll
call find_fsid_with_metadata_uuid() and get our fs_devices for this
UUID.  At this point we lock the fs_devices->device_list_mutex.  This is
what protects us in this case, but we have two cases here.

1. We aren't to the device removal part of the RM.  We found our device,
   and device name matches our path, we go down and we set total_devices
   to our super number of devices, which doesn't affect anything because
   we haven't done the remove yet.

2. We are past the device removal part, which is protected by the
   device_list_mutex.  Scan doesn't find the device, it goes down and
   does the

   if (fs_devices->opened)
	   return -EBUSY;

   check and we bail out.

Nothing about this situation is ideal, but the lockdep splat is real,
and the fix is safe, tho admittedly a bit scary looking.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ copy more from the discussion ]
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
esmil pushed a commit that referenced this pull request Nov 21, 2021
[ Upstream commit 5ec0a6f ]

Host crashes when pci_enable_atomic_ops_to_root() is called for VFs with
virtual buses. The virtual buses added to SR-IOV have bus->self set to NULL
and host crashes due to this.

  PID: 4481   TASK: ffff89c6941b0000  CPU: 53  COMMAND: "bash"
  ...
   #3 [ffff9a9481713808] oops_end at ffffffffb9025cd6
   #4 [ffff9a9481713828] page_fault_oops at ffffffffb906e417
   #5 [ffff9a9481713888] exc_page_fault at ffffffffb9a0ad14
   #6 [ffff9a94817138b0] asm_exc_page_fault at ffffffffb9c00ace
      [exception RIP: pcie_capability_read_dword+28]
      RIP: ffffffffb952fd5c  RSP: ffff9a9481713960  RFLAGS: 00010246
      RAX: 0000000000000001  RBX: ffff89c6b1096000  RCX: 0000000000000000
      RDX: ffff9a9481713990  RSI: 0000000000000024  RDI: 0000000000000000
      RBP: 0000000000000080   R8: 0000000000000008   R9: ffff89c64341a2f8
      R10: 0000000000000002  R11: 0000000000000000  R12: ffff89c648bab000
      R13: 0000000000000000  R14: 0000000000000000  R15: ffff89c648bab0c8
      ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
   #7 [ffff9a9481713988] pci_enable_atomic_ops_to_root at ffffffffb95359a6
   #8 [ffff9a94817139c0] bnxt_qplib_determine_atomics at ffffffffc08c1a33 [bnxt_re]
   #9 [ffff9a94817139d0] bnxt_re_dev_init at ffffffffc08ba2d1 [bnxt_re]

Per PCIe r5.0, sec 9.3.5.10, the AtomicOp Requester Enable bit in Device
Control 2 is reserved for VFs.  The PF value applies to all associated VFs.

Return -EINVAL if pci_enable_atomic_ops_to_root() is called for a VF.

Link: https://lore.kernel.org/r/1631354585-16597-1-git-send-email-selvin.xavier@broadcom.com
Fixes: 35f5ace ("RDMA/bnxt_re: Enable global atomic ops if platform supports")
Fixes: 430a236 ("PCI: Add pci_enable_atomic_ops_to_root()")
Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Andy Gospodarek <gospo@broadcom.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
esmil pushed a commit that referenced this pull request Nov 21, 2021
commit 2aa3660 upstream.

It is generally unsafe to call put_device() with dpm_list_mtx held,
because the given device's release routine may carry out an action
depending on that lock which then may deadlock, so modify the
system-wide suspend and resume of devices to always drop dpm_list_mtx
before calling put_device() (and adjust white space somewhat while
at it).

For instance, this prevents the following splat from showing up in
the kernel log after a system resume in certain configurations:

[ 3290.969514] ======================================================
[ 3290.969517] WARNING: possible circular locking dependency detected
[ 3290.969519] 5.15.0+ #2420 Tainted: G S
[ 3290.969523] ------------------------------------------------------
[ 3290.969525] systemd-sleep/4553 is trying to acquire lock:
[ 3290.969529] ffff888117ab1138 ((wq_completion)hci0#2){+.+.}-{0:0}, at: flush_workqueue+0x87/0x4a0
[ 3290.969554]
               but task is already holding lock:
[ 3290.969556] ffffffff8280fca8 (dpm_list_mtx){+.+.}-{3:3}, at: dpm_resume+0x12e/0x3e0
[ 3290.969571]
               which lock already depends on the new lock.

[ 3290.969573]
               the existing dependency chain (in reverse order) is:
[ 3290.969575]
               -> #3 (dpm_list_mtx){+.+.}-{3:3}:
[ 3290.969583]        __mutex_lock+0x9d/0xa30
[ 3290.969591]        device_pm_add+0x2e/0xe0
[ 3290.969597]        device_add+0x4d5/0x8f0
[ 3290.969605]        hci_conn_add_sysfs+0x43/0xb0 [bluetooth]
[ 3290.969689]        hci_conn_complete_evt.isra.71+0x124/0x750 [bluetooth]
[ 3290.969747]        hci_event_packet+0xd6c/0x28a0 [bluetooth]
[ 3290.969798]        hci_rx_work+0x213/0x640 [bluetooth]
[ 3290.969842]        process_one_work+0x2aa/0x650
[ 3290.969851]        worker_thread+0x39/0x400
[ 3290.969859]        kthread+0x142/0x170
[ 3290.969865]        ret_from_fork+0x22/0x30
[ 3290.969872]
               -> #2 (&hdev->lock){+.+.}-{3:3}:
[ 3290.969881]        __mutex_lock+0x9d/0xa30
[ 3290.969887]        hci_event_packet+0xba/0x28a0 [bluetooth]
[ 3290.969935]        hci_rx_work+0x213/0x640 [bluetooth]
[ 3290.969978]        process_one_work+0x2aa/0x650
[ 3290.969985]        worker_thread+0x39/0x400
[ 3290.969993]        kthread+0x142/0x170
[ 3290.969999]        ret_from_fork+0x22/0x30
[ 3290.970004]
               -> #1 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}:
[ 3290.970013]        process_one_work+0x27d/0x650
[ 3290.970020]        worker_thread+0x39/0x400
[ 3290.970028]        kthread+0x142/0x170
[ 3290.970033]        ret_from_fork+0x22/0x30
[ 3290.970038]
               -> #0 ((wq_completion)hci0#2){+.+.}-{0:0}:
[ 3290.970047]        __lock_acquire+0x15cb/0x1b50
[ 3290.970054]        lock_acquire+0x26c/0x300
[ 3290.970059]        flush_workqueue+0xae/0x4a0
[ 3290.970066]        drain_workqueue+0xa1/0x130
[ 3290.970073]        destroy_workqueue+0x34/0x1f0
[ 3290.970081]        hci_release_dev+0x49/0x180 [bluetooth]
[ 3290.970130]        bt_host_release+0x1d/0x30 [bluetooth]
[ 3290.970195]        device_release+0x33/0x90
[ 3290.970201]        kobject_release+0x63/0x160
[ 3290.970211]        dpm_resume+0x164/0x3e0
[ 3290.970215]        dpm_resume_end+0xd/0x20
[ 3290.970220]        suspend_devices_and_enter+0x1a4/0xba0
[ 3290.970229]        pm_suspend+0x26b/0x310
[ 3290.970236]        state_store+0x42/0x90
[ 3290.970243]        kernfs_fop_write_iter+0x135/0x1b0
[ 3290.970251]        new_sync_write+0x125/0x1c0
[ 3290.970257]        vfs_write+0x360/0x3c0
[ 3290.970263]        ksys_write+0xa7/0xe0
[ 3290.970269]        do_syscall_64+0x3a/0x80
[ 3290.970276]        entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 3290.970284]
               other info that might help us debug this:

[ 3290.970285] Chain exists of:
                 (wq_completion)hci0#2 --> &hdev->lock --> dpm_list_mtx

[ 3290.970297]  Possible unsafe locking scenario:

[ 3290.970299]        CPU0                    CPU1
[ 3290.970300]        ----                    ----
[ 3290.970302]   lock(dpm_list_mtx);
[ 3290.970306]                                lock(&hdev->lock);
[ 3290.970310]                                lock(dpm_list_mtx);
[ 3290.970314]   lock((wq_completion)hci0#2);
[ 3290.970319]
                *** DEADLOCK ***

[ 3290.970321] 7 locks held by systemd-sleep/4553:
[ 3290.970325]  #0: ffff888103bcd448 (sb_writers#4){.+.+}-{0:0}, at: ksys_write+0xa7/0xe0
[ 3290.970341]  #1: ffff888115a14488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x103/0x1b0
[ 3290.970355]  #2: ffff888100f719e0 (kn->active#233){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x10c/0x1b0
[ 3290.970369]  #3: ffffffff82661048 (autosleep_lock){+.+.}-{3:3}, at: state_store+0x12/0x90
[ 3290.970384]  #4: ffffffff82658ac8 (system_transition_mutex){+.+.}-{3:3}, at: pm_suspend+0x9f/0x310
[ 3290.970399]  #5: ffffffff827f2a48 (acpi_scan_lock){+.+.}-{3:3}, at: acpi_suspend_begin+0x4c/0x80
[ 3290.970416]  #6: ffffffff8280fca8 (dpm_list_mtx){+.+.}-{3:3}, at: dpm_resume+0x12e/0x3e0
[ 3290.970428]
               stack backtrace:
[ 3290.970431] CPU: 3 PID: 4553 Comm: systemd-sleep Tainted: G S                5.15.0+ #2420
[ 3290.970438] Hardware name: Dell Inc. XPS 13 9380/0RYJWW, BIOS 1.5.0 06/03/2019
[ 3290.970441] Call Trace:
[ 3290.970446]  dump_stack_lvl+0x44/0x57
[ 3290.970454]  check_noncircular+0x105/0x120
[ 3290.970468]  ? __lock_acquire+0x15cb/0x1b50
[ 3290.970474]  __lock_acquire+0x15cb/0x1b50
[ 3290.970487]  lock_acquire+0x26c/0x300
[ 3290.970493]  ? flush_workqueue+0x87/0x4a0
[ 3290.970503]  ? __raw_spin_lock_init+0x3b/0x60
[ 3290.970510]  ? lockdep_init_map_type+0x58/0x240
[ 3290.970519]  flush_workqueue+0xae/0x4a0
[ 3290.970526]  ? flush_workqueue+0x87/0x4a0
[ 3290.970544]  ? drain_workqueue+0xa1/0x130
[ 3290.970552]  drain_workqueue+0xa1/0x130
[ 3290.970561]  destroy_workqueue+0x34/0x1f0
[ 3290.970572]  hci_release_dev+0x49/0x180 [bluetooth]
[ 3290.970624]  bt_host_release+0x1d/0x30 [bluetooth]
[ 3290.970687]  device_release+0x33/0x90
[ 3290.970695]  kobject_release+0x63/0x160
[ 3290.970705]  dpm_resume+0x164/0x3e0
[ 3290.970710]  ? dpm_resume_early+0x251/0x3b0
[ 3290.970718]  dpm_resume_end+0xd/0x20
[ 3290.970723]  suspend_devices_and_enter+0x1a4/0xba0
[ 3290.970737]  pm_suspend+0x26b/0x310
[ 3290.970746]  state_store+0x42/0x90
[ 3290.970755]  kernfs_fop_write_iter+0x135/0x1b0
[ 3290.970764]  new_sync_write+0x125/0x1c0
[ 3290.970777]  vfs_write+0x360/0x3c0
[ 3290.970785]  ksys_write+0xa7/0xe0
[ 3290.970794]  do_syscall_64+0x3a/0x80
[ 3290.970803]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 3290.970811] RIP: 0033:0x7f41b1328164
[ 3290.970819] Code: 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 80 00 00 00 00 8b 05 4a d2 2c 00 48 63 ff 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 f3 c3 66 90 55 53 48 89 d5 48 89 f3 48 83
[ 3290.970824] RSP: 002b:00007ffe6ae21b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[ 3290.970831] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f41b1328164
[ 3290.970836] RDX: 0000000000000004 RSI: 000055965e651070 RDI: 0000000000000004
[ 3290.970839] RBP: 000055965e651070 R08: 000055965e64f390 R09: 00007f41b1e3d1c0
[ 3290.970843] R10: 000000000000000a R11: 0000000000000246 R12: 0000000000000004
[ 3290.970846] R13: 0000000000000001 R14: 000055965e64f2b0 R15: 0000000000000004

Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
esmil pushed a commit that referenced this pull request Dec 12, 2021
When reading the voltage:

$ cat /sys/bus/iio/devices/iio\:device0/in_voltage0_raw

Lockdep complains:

[  153.910616] ======================================================
[  153.916918] WARNING: possible circular locking dependency detected
[  153.923221] 5.14.0+ #5 Not tainted
[  153.926692] ------------------------------------------------------
[  153.932992] cat/717 is trying to acquire lock:
[  153.937525] c2585358 (&indio_dev->mlock){+.+.}-{3:3}, at: iio_device_claim_direct_mode+0x28/0x44
[  153.946541]
               but task is already holding lock:
[  153.952487] c2585860 (&dln2->mutex){+.+.}-{3:3}, at: dln2_adc_read_raw+0x94/0x2bc [dln2_adc]
[  153.961152]
               which lock already depends on the new lock.

Fix this by not calling into the iio core underneath the dln2->mutex lock.

Fixes: 7c0299e ("iio: adc: Add support for DLN2 ADC")
Cc: Jack Andersen <jackoalan@gmail.com>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://lore.kernel.org/r/20211018113731.25723-1-noralf@tronnes.org
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
esmil pushed a commit that referenced this pull request Dec 12, 2021
With preemption enabled (CONFIG_DEBUG_PREEMPT=y), the following appeared
when rnbd client tries to map remote block device.

  BUG: using smp_processor_id() in preemptible [00000000] code: bash/1733
  caller is debug_smp_processor_id+0x17/0x20
  CPU: 0 PID: 1733 Comm: bash Not tainted 5.16.0-rc1 #5
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-0-g155821a-rebuilt.opensuse.org 04/01/2014
  Call Trace:
   <TASK>
   dump_stack_lvl+0x5d/0x78
   dump_stack+0x10/0x12
   check_preemption_disabled+0xe4/0xf0
   debug_smp_processor_id+0x17/0x20
   rtrs_clt_update_all_stats+0x3b/0x70 [rtrs_client]
   rtrs_clt_read_req+0xc3/0x380 [rtrs_client]
   ? rtrs_clt_init_req+0xe3/0x120 [rtrs_client]
   rtrs_clt_request+0x1a7/0x320 [rtrs_client]
   ? 0xffffffffc0ab1000
   send_usr_msg+0xbf/0x160 [rnbd_client]
   ? rnbd_clt_put_sess+0x60/0x60 [rnbd_client]
   ? send_usr_msg+0x160/0x160 [rnbd_client]
   ? sg_alloc_table+0x27/0xb0
   ? sg_zero_buffer+0xd0/0xd0
   send_msg_sess_info+0xe9/0x180 [rnbd_client]
   ? rnbd_clt_put_sess+0x60/0x60 [rnbd_client]
   ? blk_mq_alloc_tag_set+0x2ef/0x370
   rnbd_clt_map_device+0xba8/0xcd0 [rnbd_client]
   ? send_msg_open+0x200/0x200 [rnbd_client]
   rnbd_clt_map_device_store+0x3e5/0x620 [rnbd_client

To supress the calltrace, let's call get_cpu_ptr/put_cpu_ptr pair in
rtrs_clt_update_rdma_stats to disable preemption when accessing per-cpu
variable.

While at it, let's make the similar change in rtrs_clt_update_wc_stats.
And for rtrs_clt_inc_failover_cnt, though it was only called inside rcu
section, but it still can be preempted in case CONFIG_PREEMPT_RCU is
enabled, so change it to {get,put}_cpu_ptr pair either.

Link: https://lore.kernel.org/r/20211128133501.38710-1-guoqing.jiang@linux.dev
Signed-off-by: Guoqing Jiang <guoqing.jiang@linux.dev>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
esmil pushed a commit that referenced this pull request Dec 12, 2021
When kmalloc in nfc_genl_dump_devices() fails then
nfc_genl_dump_devices_done() segfaults as below

KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 0 PID: 25 Comm: kworker/0:1 Not tainted 5.16.0-rc4-01180-g2a987e65025e-dirty #5
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-6.fc35 04/01/2014
Workqueue: events netlink_sock_destruct_work
RIP: 0010:klist_iter_exit+0x26/0x80
Call Trace:
<TASK>
class_dev_iter_exit+0x15/0x20
nfc_genl_dump_devices_done+0x3b/0x50
genl_lock_done+0x84/0xd0
netlink_sock_destruct+0x8f/0x270
__sk_destruct+0x64/0x3b0
sk_destruct+0xa8/0xd0
__sk_free+0x2e8/0x3d0
sk_free+0x51/0x90
netlink_sock_destruct_work+0x1c/0x20
process_one_work+0x411/0x710
worker_thread+0x6fd/0xa80

Link: https://syzkaller.appspot.com/bug?id=fc0fa5a53db9edd261d56e74325419faf18bd0df
Reported-by: syzbot+f9f76f4a0766420b4a02@syzkaller.appspotmail.com
Signed-off-by: Tadeusz Struk <tadeusz.struk@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20211208182742.340542-1-tadeusz.struk@linaro.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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